PML-N Vice President Maryam Nawaz on Monday strongly criticised the arrest of her uncle and party president Shehbaz Sharif, saying he was being "punished" for standing by his brother former prime minister Nawaz Sharif's side.

She was addressing a press conference alongside other top leaders of the PML-N, hours after Leader of the Opposition in the National Assembly Shehbaz was arrested by the National Accountability Bureau (NAB) after the Lahore High Court rejected his bail plea in a money laundering case.

Shehbaz was taken into custody from the court's premises, where a large number of PML-N workers and supporters had gathered ahead of the hearing.

In a tweet, Nawaz said "this puppet government has endorsed the resolution adopted by the opposition's [multi-party conference].

"Shehbaz Sharif had already said all of the [MPC's] decisions would be implemented whether he is in prison or outside. No one should be mistaken that such disgraceful tactics will make us bow down."

Speaking at the news conference, Maryam said today was a "very sad day" because the opposition leader had been arrested again.

"I don't have a grain of doubt that Shehbaz Sharif was not arrested for corruption or accountability. A reference against him was ongoing and he was arrested in the middle," she said, adding that the only reason Shehbaz was arrested was that he "has not left his brother's side".

"He not only did not leave his brother's side, but he showed loyalty and commitment to his brother and his cause and did not waiver for a second. His wife and children were made absconders, [his son] Hamza is in jail and has corona.

"Despite this, he stands with his brother unwaveringly," she said, adding that Shehbaz had last week made it clear that even if he was arrested, the speech made by PML-N supremo Nawaz Sharif at the opposition's Sept 20 multi-party conference and the MPC statement and action plan would be followed "100 per cent".

She said Shehbaz was "not arrested on any allegation" but for standing by his brother's words.

Referring to a recent controversy generated by a news report regarding the offshore business assets of Prime Minister Imran Khan's aide Lt Gen Asim Saleem Bajwa's family, Maryam said: "If there is even a semblance of law and justice [in the country], then instead of Shehbaz Sharif, Asim Bajwa should have been arrested."

She said Shehbaz belonged to a business family and his father had an expansive business.

"Bajwa is a salaried person and for him to become a billionaire is an accountable allegation," she added. "The companies and franchises that have come forward ... NAB used to say that it doesn't see the face, it sees the case; can't they see it now [in Bajwa's case]?

She also questioned why NAB allegedly did not move against Peshawar "Bus Rapid Transit (BRT) project or its buses catching fire, the Billion Tree Tsunami programme, regularisation of [PM] Imran Khan's house, corruption of ministers or the departure of Jahangir Tareen".

"When Bajwa's assets came forward and with his wife being a housewife, did NAB not see the case? Did Imran Khan not see the case? Does no one see their children and their assets? So what kind of justice is this?"

Maryam claimed that the media was "blackmailed" against running the news regarding Bajwa's family assets but was later asked to run the clarification issued by him.

"Nothing can make [institutions] more controversial than using them and blackmailing judges," she said.

"Sometimes Maulana [Fazlur Rehman] is sent a notice, at others Shehbaz Sharif is arrested, but does anyone have the courage to send a notice to Asim Bajwa?"

"S (sheen) will not separate from N (noon)," she said, referring to Shehbaz and the PML-N.

Speaking of the "brotherhood" between Shehbaz and Nawaz, Maryam said although Shehbaz personally considered "politics of reconciliation" to be better, "when Nawaz Sharif takes a decision, Shehbaz is the first to implement it."

She said "in the eyes of the people, especially in Punjab, Shehbaz Sharif is not the alternative [to PM Imran Khan] but he is the only choice."

"No one has brought more disrepute to the institutions than" the PTI government, Maryam alleged.

"As far as the [MPC] agenda and its implementation is concerned, whether you arrest Shehbaz Sharif or Maryam Nawaz or our PML-N workers, this movement will not be stopped; it will go on and will go on with full passion."

The PML-N leader alleged that pre-poll rigging was being carried out in Gilgit-Baltistan. "Whether the PML-N wins or loses, we won't let you get away with it so easily. If you want to do [political] engineering and you want to steal these elections then you will have to do it in front of the people's eyes. You can't do it secretly so the repercussions of this will be also for you along with the PML-N," she said.

Condemning Shehbaz's arrest, PML-N leader Ahsan Iqbal said it was "tragic" that a person "who worked tirelessly for Punjab and served the poor and the widows and the less unfortunate has today been treated in such a manner".

He said a meeting of the Pakistan Democratic Movement had been called so that the opposition parties could decide a strategy.

"PML-N in every corner of the country will protest against this. We will call for the requisition of National Assembly and Senate sessions to protest as well.

"But we want to give a message to the federal government that if you have beaten the drum of war then we will fight this war and win it," he added.

'DG ISPR shouldn't have become a party in Zubair-COAS meetings'

Maryam was asked to comment on Inter-Services Public Relations (ISPR) Director General Maj Gen Babar Iftikhar's revelation that PML-N leader Mohammad Zubair had held two meetings with Army Chief Gen Qamar Javed Bajwa to talk about Nawaz and Maryam.

"It's obvious that when you meet for four hours and talk and eat together, he would talk about Nawaz and Maryam being from the PML-N.

"I think the DG ISPR is a decent person; he has conducted himself very decently, [but] he should not have become a party in this and given a personal meeting a political colour," she replied.

"In reply [to the ISPR chief], if we had said what we knew, then that would have been considered a bad thing," she added.

Answering a question about a recent protest outside Nawaz's London residence, Maryam said the protesters "did not have the courage" to show their faces and were wearing hoodies and face coverings.

"It is is the biggest folly to think that Nawaz Sharif would be scared [by such tactics] after suffering everything."

Asked about her father Nawaz's return, Maryam said he would "come back soon".

"It is very difficult for him to stay away from the country at 72. He has one heart surgery left to undergo, so no one in the party wants him to come back without getting treatment.

"He is ill but his passion is not. He will lead the party with full enthusiasm [and] people who thought he had been ousted from the government will be left rubbing their hands."

Relations between the PTI-led government and opposition have become tenser in recent days after the latter held a conference where they announced a wide-ranging anti-government movement and criticised the military's interference in politics. Following the MPC, in which Nawaz had bitterly criticised the army for interfering in politics, a number of revelations came to the fore regarding civil-military meetings.

Prime Minister Imran reportedly said he was aware of the meetings, and accused the opposition of wanting to create a rift between the government and the armed forces.