Pakistan Tehreek-i-Insaf (PTI) Chairman Imran Khan speaking to journalists in Islamabad on Wednesday alleged that one Javed Sadiq is a frontman for Punjab Chief Minister Shahbaz Sharif.

The PTI chief waved a sheaf of papers which allegedly contained contract and consultancy details and said they would be shared with the media soon.

"He has eaten Rs 15 billion, and has an additional Rs26bn by now," he claimed. "He is Shahbaz Sharif's frontman. He takes money for Shahbaz Sharif," the PTI chief alleged.

Imran said he would bring forth more proof of 'corruption' by Nov 2, the date set for the PTI's planned 'lockdown' of Islamabad.

The party has said it will stage a protest unless Prime Minister Nawaz Sharif agrees to an investigation into the Panama Papers leaks under the terms of reference proposed by the opposition or resigns from his position.

Imran Khan has repeatedly demanded a response to accusations of corruption levelled against Nawaz and his family in the wake of Panama Papers which he maintains are "proof of corruption", not allegations.