The department, through the Finance Ministry, has written to a number of foreign tax authorities as details of stashed funds on more than 60 per cent of those named on the list show the bank balances of a particular day rather than the entire financial transactions done by the individual or the account holder.

Sources said in most of the cases featuring on the secret list, either the bank balances are very small or show 'nil' amounts without stating the actual amount of funds secretly hidden by the individual.

The I-T and the Finance Ministry, hence, has now approached a few countries including Switzerland and France to allow them access to the 'full transaction activity' of these entities from the period the accounts were opened.

"The communication with foreign tax authorities are being done under the provisions of the Double Taxation Avoidance Agreement (DTAA)," sources said.

Apart from the alpine nation where the bank had its branch, the I-T has written to few more unspecified countries after a probe by enforcement agencies showed that the featured entities could have invested funds at these offshore locations in order to evade the tax scanner.

The I-T has already decided to begin prosecution action against those having "substantial" amounts in their bank accounts shown in this list.

The department has also begun a country-wide I-T assessment of those persons whose names have figured in these lists.