The Financial Intelligence Unit, country's anti-money laundering agency, has helped the income tax authorities identify more than 60 big tax evaders who had been untraceable for several years.

Finance ministry officials said the I-T department is now planning a crackdown, hoping to step up collections to meet the total direct tax mopup target of Rs 5.33 lakh crore.

The FIU has linked more than 350 bank accounts with these evaders. These bank accounts had recorded "active transactions" during the surveillance, a ministry official said.

Some of these evaders had declared themselves bankrupt but this did not prevent them from acquiring fresh assets.

"Success rate with the FIU data has been very good," the official said.

Finance minister Pranab Mukherjee had set up a dedicated cell to monitor information from various agencies to ensure that tax evaders are nabbed.

Direct tax arrears stood at Rs 3.3 lakh crore on March 31, 2011. Of this, personal income tax was Rs 1.97 lakh crore and corporate tax Rs 1.4 lakh crore.

An audit by the Comptroller and Auditor General found that as of September 30, 2010, Rs 1.65 lakh crore of arrears could not be realized, of which nearly Rs 90,000 crore was on account of the assessee not being traceable or not having enough assets to enable recovery.

The FIU, which receives data on financial transactions from banks and other financial institutions, was given a list of 271 cases from which recoveries could be made.

The Prevention of Money Laundering Act requires banks, financial institutions and intermediaries of securities markets to file 10-year records of individuals who have executed transactions of a value exceeding Rs 10 lakh and of individuals involved in "suspicious transactions".

Data from other sources such as Annual Information Return, available with the income-tax department, are also being matched to create profiles of these evaders.

The issue of tax evasion and black money has come under intense public and court scrutiny over the past year, forcing the government to step up efforts to tackle the menace.

The finance ministry has set up a committee of senior tax officials to examine ways to curb black money generation and its illegal transfer abroad. It has also instituted a national study to quantify unaccounted wealth within and outside the country. The panel's report is expected shortly.