Need extra cash this time of the year? Maybe you're owed a federal tax refund.

The IRS yesterday announced that 3,538 taxpayers in Pennsylvania are owed $6,347,540, or an average refund of $1,794.

In Philadelphia, 855 taxpayers are owed more than $1.9 million, or an average of $2,288 each, said spokesman Mark Hanson.

The tax refunds, from 2009 and previous tax years, were returned to the IRS as undeliverable. Hanson said the causes for the undeliverable returns were, for the most part, people moving and not updating their addresses or an error in the address on the return.

Philadelphia residents who are owed tax returns are on a list provided by the IRS. You can find the list at philly.com/freemoney.

"We want to make sure taxpayers get the money owed to them," IRS Commissioner Doug Shulman said in a statement. "If you think you are missing a refund, the sooner you update your address information, the quicker you can get your money."

Nationwide, undelivered refund checks average $1,471 this year, compared to $1,148 last year. Some taxpayers are due more than one check.

If you are owed money, you need to update your address to get your check. You can do so on the IRS.gov website by clicking on the "Check on Your Refund" link on the left. You can also call 1-800-829-1954.

You will need your Social Security Number (or Individual Taxpayer Identification Number), your filing status (such as single, married filing jointly or married filing separately) and the exact whole-dollar amount of your refund.

The IRS encourages people to file their tax returns electronically to reduce errors and eliminate the risk of lost-paper returns.

The governmental agency also advises people to be aware of e-mail scams. The IRS does not contact taxpayers by e-mail to alert them of pending refunds, the agency said.

To see if you are owed any money from the IRS, go to philly.com/freemoney