TALLAHASSEE, Fla. (AP) _ Gov. Bob Martinez denied Tuesday that he lied while testifying in a criminal trial last week, and asked White House officials to oust his accuser, U.S. Attorney Robert W. Merkle.

An aide to the Republican governor said that Martinez plans to ask President Reagan to nominate someone else for the job. Merkle's four-year appointment as federal prosecutor for the middle district of Florida expired in April, but he has remained in office.

Martinez spoke with presidential assistant Mitch Daniels by telephone and was told Reagan would definitely hear his request, said J.M. ''Mac'' Stipanovich, Martinez' chief of staff for external affairs.

Martinez has asked Rep. Bill Young, R-Fla., to poll the state's GOP congressional delegation to find a consensus candidate for the governor to send to Reagan, said Harry Glenn, a spokesman for Young.

If Reagan chose to renominate Merkle, Stipanovich predicted the Senate would not confirm him. He said the state's two Democratic senators, Lawton Chiles and Bob Graham, ''could persuade their colleagues to inquire into the conduct of his office.''

A spokesman for Chiles, Jack Pridgen, said the senator didn't think he could support Merkle's renomination, but ''would still listen to whatever testimony was presented.''

Merkle told jurors in Tampa on Monday that the governor, who was summoned as a defense witness in a mail-fraud trial, had lied to them.

''I did not lie on the stand,'' Martinez said Tuesday in Tallahassee.

Martinez testified for five hours over two days last week in the mail-fraud trial of businessman Nelson A. Italiano. Martinez has not been charged with any wrongdoing.

Merkle's key government witness, Eddie Perdomo, had earlier testified he gave Martinez, then a candidate for Tampa mayor, $8,000, half in cash and the rest in four checks in exchange for backing a cable television firm represented by Italiano.

The governor, called by Italiano attorneys, testified that he had received only three checks from Perdomo as campaign contributions and no cash.

Merkle told jurors, ''The fact is there was a fourth check,'' and Martinez took the money ''and put it in his pocket.''

Stipanovich said the governor wasn't alone in wanting Merkle's ouster.

''The governor feels angry,'' he said. ''It's not just Bob Martinez. A lot of people have been severely damaged and ruined by investigations made very public that went nowhere.''

Merkle said that until the trial is over, he will not comment on the case, his feud with Martinez or the governor's call for his ouster. The jury is scheduled to begin deliberations Wednesday.