The nation's chief tax collector is urging Americans to file returns early this year and said the IRS for its part will fully respect a new "taxpayer bill of rights" and try to provide filers better advice.

Lawrence B. Gibbs, commissioner of the Internal Revenue Service, said of the taxpayer-rights bill at a news conference."We feel it is a good bill . . . (and) we are going to implement the letter as well as the spirit of the law,"The legislation, enacted in reponse to scattered reports of abuses by IRS employees, requires the agency to fully inform taxpayers of their rights any time an audit is begun. Other provisions extend the notice required before the IRS can seize property and prohibit the agency from promoting employees on the basis of how much they collect.

Gibbs acknowledged that IRS employees gave the wrong answer to one of every four technical questions asked last filing season. "We were not satisfied last year," he said, "and we've gone back to the drawing board . . . to try to improve accuracy levels."

"We hope to improve substantially this year," said Robert LeBaube, director of taxpayer services. One significant factor, he said, is that the IRS was able to put on the permanent payroll 1,000 "telephone assisters" who in past years would have been hired only for the tax season. This allowed the agency to intensify the training of those employees.

"There is a clear correlation between experience and accuracy," LeBaube said.

In addition, the number of assisters working under each supervisor has been reduced from about 20 to about 12, he said.

Gibbs said the IRS is convinced that taxpayers who file early, avoiding time pressures that grow near the filing deadline, are much more likely to have an error-free return. For that reason, the IRS, the Advertising Council and the news media are combining efforts again this year to deliver the "file early" message.

"Make your taxes less taxing," read the print ads. "Do them today."

The television commercials attempt, in a good-natured way, to scare taxpayers into not waiting until the April 17 filing deadline. "Why let it haunt you when you can do something about it? asks one commercial featuring a howling wind and a bewildered taxpayer who might have stepped off another planet.

Gibbs said most taxpayers will have less to be confused about than they did a year ago. Most of the hundreds of changes brought about by the 1986 tax overhaul showed up for the first time on returns filed last year. There are very few significant changes affecting returns that will be filed this year.

Early filers are likely to get any refund within three or four weeks, Gibbs said. Those who file in late March or April may have to wait six weeks or longer.

Taxpayers in 36 states who qualify for refunds may be able to file their returns electronically this year. The remaining states will be added next year. As many as 2 million returns - four times the number last year - are expected to be filed electronically this year, Gibbs said.

Electronic returns must be filed through paid professional return preparers, from one computer to another. This significantly reduces IRS paperwork.

The agency expects 109 million returns to be filed this year, up from 107 million a year ago. About three of every four will generate refunds.