The I-T department has asked tax payers not to give out personal details like PAN card number and information about their credit cards on the internet in the wake of mushrooming fake e-mails hitting users' inboxes.

Viewing with concern the spurt in fictitious and unauthorised e-mails landing in personal internet addresses of many people, the department is adding a word of 'caution' at the end of each mail sent by them.

"A number of tax payers have received e-mails with subjects like "tax refund" and "seeking refunds" prompting us to take such measures. Such messages continue to land in big numbers in individual e-mails," a senior I-T department official said.

The department has also asked tax payers to avoid replying to e-mail addresses like "lhxbkw@accounts.Net, cvhfvs@accounts.Net and nvfmfi@accounts.Net".

These are some of the e-mail id's which have been found to be fake. Unauthorised e-mail addresses could be more than the reported ones and hence taxpayers should avoid them. The I-T department mail is only to be read and keep oneself updated but not to be replied, the official said.

"Income Tax Department does not send e-mails regarding refunds and does not seek any taxpayer information like user name, password, details of ATM, bank accounts, credit cards, etc. Taxpayers are advised not to part with such information on the basis of emails," the department has said at the end of e-mails.

In case of genuine I-T e-mails, they have been appended with a note saying "this is a computer generated mail and calls for no signature", the official said.

Following a spate of complaints about such e-mails, the Central Board of Direct Taxes (CBDT), the administrative authority of the I-T department, had in October cautioned tax payers against responding to the fake e-mails, saying if they do so it would be at their risk.

The department has also advised tax payers to keep their user id and password in a secured manner, not to share it with any other entity and suggested that the password should be changed periodically when checking tax credit statements online.