The income-tax department is likely to summon all those Indians whose names appeared in the Panama Papers and seek sworn declarations on whether they held any undisclosed offshore accounts, and the purpose if that is the case, said people dealing with the matter.

Names of about 500 Indians, including top industrialists and Bollywood actors, featured in the millions of documents leaked from Mossack Fonseca, the Panama law firm that is at the centre of a massive global controversy for allegedly helping wealthy and powerful people in making shady and secret investments. The move to summon the Indians comes two weeks after the tax department sent notices to about 50 of them.

The persons were asked how their names featured in the documents. The government is checking whether they siphoned off money earned in India to tax havens, or violated any law while making investments abroad.

"Summons would be sent to everyone (named in the papers). Then their statement on oath would be recorded," said a person with knowledge of the matter. The notices could be sent within two months.

Income Tax department likely to summon all Indians named in Panama Papers

The enforcement directorate, a finance ministry wing that probes money-laundering cases, may also assist the tax department in the investigations, especially in collecting evidences, people in the know said.

An email sent to the office of the revenue secretary seeking comment didn't elicit any response until press time on Tuesday.

Legal and tax experts said their clients linked to the Panama Papers are worried about making statement on oath because they cannot change it later. Many of them also fear harassment by tax officers, a tax consultant said.

"The tax officers can demand explanations of income generated and tax paid in the last 16 years," said the tax consultant, who is helping a client in the Panama leak issue.

This means, the tax department can dig up cases from as early as 2000 to see if taxes had been paid.

India is also considering seeking information from the Panama government about the Indians linked to the Panama Papers, said a person in the know.

"Government would require bank statements if it were to prove a wrongdoing in the court of law," said a tax lawyer. Many of the people who figure in the papers could deny any links with the offshore deals. "The onus then, to provide evidence of otherwise, would be on the tax authorities," the lawyer added.