By April 1 most of the nation’s workers will find the amounts on their paychecks a little higher than they used to be. That’s the date for implementation of the federal tax break known as Making Work Pay.

A few taxpayers, however, could find themselves owing more to the federal government next year at tax time if they aren’t careful.

New Internal Revenue Service withholding tables show some groups of workers may end up paying back next year what they got this year. Those affected could be dual-income households and individuals with multiple jobs.

The best way to find out the effect on you is to check with your employer and find out the steps to take to avoid owing extra money next year at this time. Or you can go to the IRS Web site, where there are new withholding tables. It may be necessary to adjust your W-4 withholding form.

Thieves looking for potential victims are conjuring up all sorts of tax scams. The No. 1 method is online phishing, according to the IRS. That involves sending e-mails to people designed to get them to reveal confidential information about bank accounts, credit cards and more. The IRS maintains it never uses e-mail to contact taxpayers about their personal tax issues.

More than 90 percent of the 52 million tax returns filed so far this year have been electronically filed, the IRS said.