Imran Khan said a draft of the law will be presented in parliament in the coming days. (File)

Pakistani Prime Minister Imran Khan on Sunday promised a new law that will reward whistleblowers who help nab corrupt officials and politicians.

Khan's Pakistan Tehreek-e-Insaf party won the July election campaigning on an anti-corruption reformist agenda, and has blamed the country's economic woes on the alleged corrupt practices of his predecessors.

With Pakistan facing a balance-of-payments crisis, Khan said recovering that stolen wealth would help ease the burden on the country's economy.

He has claimed that billions of dollars of public money have been stolen over the last few decades, much of it laundered out of the country.

"The law will invite countrymen to identify the corrupt and (whistleblowers will) get 20 percent of the ill-gotten money and assets recovered from such people," Khan told a press conference in the eastern city of Lahore.

The other 80 percent would be used to pay off Pakistan's debts, he said.

Khan did not give any further details, but said a draft of the law will be presented in parliament in the coming days, and will include protections for whistleblowers.

Pakistan's budget deficit has climbed steadily over the last five years, and foreign currency reserves have declined.

The rupee has also been repeatedly devalued in the past year, fuelling inflation.

Islamabad is likely to seek a bailout from the International Monetary Fund, which has called on the new government to act fast to stabilise Pakistan's teetering economy, warning growth will likely slow and inflation rise further.

Khan's predecessor Nawaz Sharif was ousted from office last year by the Supreme Court over alleged corruption, and is currently on bail pending appeal.

His brother Shehbaz Sharif, the current Pakistan opposition leader, was arrested on Friday for graft -- a move described as politically motivated by the brothers' Pakistan Muslim League Nawaz (PML-N) party, ahead of by-elections later this month.