Income Tax and Customs authorities check whether companies owned by former external affairs minister Natwar Singh's son Jagat and his associates Andaleeb Sehgal and Aditya Khanna have evaded duty on the $1,93,000 commission they received in the United Nations' corrupt oil-for-food scam.

The move comes a day after the Phatak Authority Report and an Action Taken Report were tabled in Parliament.

Justice Pathak indicted both Natwar and Jagat in the scam.

Finance ministry officials told PTI that as mentioned in the Action Taken Report, the Central Board of Direct Taxes and Central Board of Excise and Customs have been asked to examine these aspects.

Taxmen would find out if there was any evasion on commission on contracts secured by Andaleeb Sehgal, Jagat's relative and friend Aditya Khanna during the Saddam Hussein regime in 2001, officials said.

Even if income earned was through illegal means, the beneficiaries would have to pay tax, the officials said adding that the investigation was simple.

All that the taxmen would have to do is to go through their income tax returns and find out whether they had evaded tax on this count, they said.

If they have, then they could be prosecuted apart from being asked to pay penal interests as tax evasion is a criminal offence, the officials said. They would also examine if there were customs duty violations in the export contracts.