Close to a month into tax season, tax refunds are starting to increase.

The average check is now $3,143 for the week ended Feb. 22, according to the IRS. That's just about on par with last year's figures, reflecting a rise of 1.3 percent year over year.

The increase in refund amounts is a change from the recent downward trend of smaller checks.

Treasury Secretary Steven Mnuchin said in an interview with CNBC on Thursday that refunds were rising. "Tax refunds are up 17 percent week over week," he said. That basically gets us to the same level as last year."

The Treasury Department issued a statement saying the increase in the weekly data is primarily due to the remainder of the Earned Income Tax Credits and Child Tax Credits being paid out this week.

"Those two tax credits are one of the biggest determinants on whether an individual receives a refund," said Nicole Kaeding, vice president at the Tax Foundation, an independent, non-profit tax policy organization. "We need to be careful in not overinterpreting the data. It is still not clear whether at the end of the filing season refunds will be up or down compared to last year."

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This tax season is particularly notable for filers.

It's the first time taxpayers are submitting their returns under the Tax Cuts and Jobs Act, which took effect last year.

Taxpayers have been grappling with the overhaul, which nearly doubled the standard deduction, eliminated personal exemptions and placed limits on itemized deductions.

Since the opening of filing season on Jan. 28 and up until the week ended Feb. 15, the average refund was down compared with last year.