Former prime minister Kakuei Tanaka, who was convicted two weeks ago on a bribery charge, indicated today he would resist pressures to resign from parliament despite a heart-to-heart talk with the current premier, Yasuhiro Nakasone.

After what had been billed as their showdown meeting, the blunt-spoken Tanaka issued a statement that, uncharacteristically, was laced with humility and in which he promised to exercise prudence in his behavior from now on. But he said nothing about resigning.

From Nakasone's vague account, it was not even clear whether he had raised the issue of resignation with the political titan who helped him climb to power last year, but it seemed that he had not.

"All of these things are up to Mr. Tanaka and must be decided by Mr. Tanaka himself," Nakasone told reporters. "These are not problems in which a third party should interfere."

The result was an anticlimactic blur of words that seemed to leave Japan in the same state of political confusion that has reigned since Tanaka was convicted of bribery Oct. 12 and began rejecting all suggestions that he quit the parliament, the Diet.

The legislature has been in limbo since that day when opposition parties began a boycott over the ruling Liberal Democratic Party's refusal to consider a motion calling on Tanaka to resign.

To break the deadlock, the prime minister agreed to meet with Tanaka and perhaps, party sources had suggested, try to nudge him into a resignation.

There was no indication tonight that the widely publicized meeting in a ninth-floor suite of Tokyo's Okura Hotel had accomplished anything except angering opposition parties even more.

A member of the Socialist Party, the largest in the opposition, called the meeting "totally disappointing" and said it amounted merely to "internal talks between friends."

Even one leader of the Liberal Democrats, former prime minister Takeo Fukuda, was quoted by a television interviewer as calling the meeting "meaningless" and said the two participants' statements were so vague that it was "impossible to understand what they were talking about."

There was speculation tonight that Nakasone would take the line that he had done his best as a premier and party leader and try to get the parliament back in business. Failing that, some suggested, he would instruct Liberal Democratic members, who consititute a solid majority, to go it alone and start passing legislation.

Even that will leave the government in an embarrassing position in the coming weeks as it plays host to President Reagan and West German Chancellor Helmut Kohl.

Whichever way it turns out, Nakasone is expected to dissolve the lower house of parliament and schedule new elections in December or early in 1984. Tanaka, by all accounts, easily would be returned to office.

Tanaka and Nakasone met alone for an hour and 40 minutes this afternoon. Tanaka left without talking with reporters and later issued a statement that was read by a secretary.

He said that because the political situation is "quite serious" he would be "prudent" in the future and exert more self-discipline. He said he would "do my best" to meet the expectations of the Japanese people.

The apologetic tone was in contrast to his tough, defiant statement after the court's verdict in which he insisted he was innocent and refused to resign.

Nakasone, in his version of the conversation, said Tanaka had expressed deep apology for causing troubles both for the Japanese people and for members of the ruling party.

He said they had talked of how to resolve the political crisis and said he had done his best to give advice to Tanaka. But, asked specifically if he had urged Tanaka to resign, Nakasone said he would not disclose the substance of their talks.