Expect a sometimes frantic day at the tax preparers, accountants and post offices as procrastinators across Hawai'i work to meet a midnight deadline tonight to file their federal taxes.

The Internal Revenue Service this year estimated that 20 percent of people filing tax returns will wait until the last two weeks. IRS spokeswoman Judy Monahan says that works out to about 133,480 of the 667,400 returns expected to be filed in Hawai'i this season.

At the Taxbusters office in Kalihi, the phones were ringing, people were waiting and everyone was very busy.

Owner Hank Erwin took the seasonal crush in stride: "It's very hectic; it's normal. This is just like every other year."

Erwin said he and his staff do their best to get everything done and help all their clients.

That means 12-to-15 hour days for him every day in that final countdown to today's deadline.

People also face a deadline of midnight Sunday for getting their Hawai'i state returns completed and in the mail.

IRS officials say they expect more people may file this year to tap the economic stimulus payment available to many — even those who wouldn't normally have to file a return.

"You don't get your economic stimulus payment until you file your return," Monahan said.

If you are among the taxpayers expecting both a refund and an economic stimulus payment, Monahan said those checks will arrive separately.

About 70,000 people in Hawai'i who qualify for the economic stimulus payment may not normally be required to file a tax return and may not have done so in several years. To qualify for the minimum economic stimulus payment, people must have at least $3,000 of qualifying income in any combination income from Social Security retirement, disability or survivors' benefits; disability compensation, disability pension or survivors' benefits from the Department of Veterans Affairs; Tier 1 benefits from Railroad Retirement, certain combat pay and earned income from wages, salaries, tips or net earnings from self-employment that are included in taxable income.

Under the Economic Stimulus Act of 2008, people may be eligible for up to $600 ($1,200 for married couples) even if they are not normally required to file a tax return because their income falls below the filing requirement. There also is an additional payment of $300 for people with eligible children younger than 17 as of December 31, 2007. However, people must file an income tax return in order to receive the payment.

The stimulus payments will go out starting in May to more than 130 million households.

Monahan said more taxpayers are filing their returns electronically. "We are also expecting about 328,300 (Hawai'i returns to be) e-filed."

She urged taxpayers who have any hope of finishing their returns today to put them in the mail even if they can't pay all their taxes right away.

"Don't file an extension," she said. "File the tax return and pay when you can."

But that may not be possible if you didn't get all your documents together. Then you might need to file for more time, she said.

"You file the extension when you don't have all your paperwork," Monahan said.

But, she added, remember that if you think you owe money, you need to send in an estimate of what your tax would be because it's not an extension of time to pay.