The Internal Revenue Service posted an alert on its Web site Thursday to tell taxpayers and the tax community that it is experiencing high traffic on its online “Where's My Refund?” tool as more tax returns arrive.

The IRS delayed tax season until Jan. 30 this year and was not able to process a number of important forms until this week (see Two Major Tax Forms Ready for Filing Soon). The heavy volume of refund inquiries means that the IRS anticipates both "Where's My Refund?" on IRS.gov and the refund feature on the IRS2go phone app will have limited availability during busier periods.

“Due to the large number of inquiries and to avoid service disruptions, the IRS strongly urges taxpayers to only check on their refunds once a day,” said the IRS. “IRS systems are only updated once a day, usually overnight, and the same information is available whether on the Internet, IRS2go smartphone app or on IRS toll-free lines. While 'Where's My Refund?' is updated nightly, your account will not change that frequently.”

The IRS added that it is seeing a “good start” to the filing season, with tax refunds being issued on a timely basis. Nine out of 10 taxpayers typically receive refunds in less than 21 days when they use e-file with direct deposit, the IRS noted.

Last tax season, there were a number of delays due to new identity theft filters (see IRS Fraud Detection System Leads to Refund Delays). Late last month, when it launched tax season, the IRS promised improvements in the "Where's My Refund?" tool to provide taxpayers with a personalized tax refund date, along with improved identity theft filters (see IRS Promises Better Service as it Kicks off Tax Season).

The IRS said it expects to see the number of tax returns—and related refund inquiries—steadily increase around the President's Day holiday week.

The IRS offered the following tips to help taxpayers with their refund questions:

• Have the right tax information ready before using any of the IRS refund tools. This includes Social Security number, filing status and refund amount.

• You don't need to check “Where's My Refund?” more than once a day as your information will not change.

• To avoid system delays, the best time to check on refunds is evening and weekends.

• There is no need to call the IRS about your refund; the telephone service has the same information that is available on “Where’s My Refund?”.