Nawaz Sharif is presently serving jail term in Lahore in a corruption case (File Photo)

A special assistant to Pakistan Prime Minister Imran Khan has accused the family of former premier Nawaz Sharif of making laws in the 1990s to help them launder ill-gotten wealth.

Sharing details of alleged telegraphic transfer of Rs 17 million to Sharif's daughter Maryam Nawaz, Shahzad Akbar said the family built an empire through corruption.

Mr Akbar said everything worked in favour of the Sharif family till their names came up in the Panama Papers in 2016.

He said the transaction of Rs 17 million in Maryam Nawaz's account was made in 2008, indicating that the family was still using flexible laws of the 1990s to bring money in Pakistan and also send abroad.

He said similar transfer of money from was made in the account of Sharif's nephew Salman Shehbaz.

"I say that 90 per cent of Salman Shehbaz's wealth is based on TT (telegraphic transfer)," he said.

He said in both cases the money trail is not established and that details of the cases would be sent to the National Accountability Bureau, which is pursuing several cases against the Sharif family.

Sharif had served Pakistan as its prime minister twice in the 1990s. He is credited with liberalising the economy when he first came to power in 1990.

Mr Akbar has earlier too leveled serious charges against opposition leaders, including Sharif who is the president of the largest Opposition party, Pakistan Muslim League-Nawaz.

Meanwhile, Opposition leaders alleged Mr Akbar is on a witch-hunt at the behest of Prime Minister Imran Khan.