WASHINGTON (February 14, 2013)--The Internal Revenue Service is asking taxpayers eager to learn the status of their tax refund to limit their visits to the IRS website to once a day.

The IRS says taxpayers are overwhelming its "Where's my refund?" website and smartphone app.

The agency says its systems are only updated once a day, usually overnight, and the same information is available the website, the IRS2go smartphone app and IRS toll-free phone lines.

To avoid delays, the agency says the best time to check on refunds is in the evening and on weekends.

The IRS says nine out of 10 taxpayers typically receive refunds in less than 21 days when they file returns online and get refunds deposited directly into bank accounts.