Secretary of State Alexander M. Haig Jr. told President Reagan last Sunday that Argentina is being "a little more flexible than the British" in trying to resolve the Falkland Islands dispute, according to a partial transcript of a conversation between the two reported yesterday by syndicated columnist Jack Anderson.

The phone conversation reportedly took place Sunday night as Haig was flying to London for his second round of talks with British leaders and as Reagan was vacationing in the Caribbean.

The State Department and the White House have declined to comment on the report.

"It's obvious from the transcript that it's the British who worry Reagan and Haig," Anderson wrote, quoting the president as saying of Britain: "They'll want a skirmish to save face."

According to the report, Reagan and Haig feared most at the time of their conversation that military action would occur before both sides could be persuaded to accept a U.S.-sponsored proposal to have an international peace-keeping force take over the disputed islands.

The conversation makes it clear, Anderson reported, that Reagan was confident in Haig's skill at shuttle diplomacy but gloomy about prospects for his mission. "Do what you can," the president reportedly told Haig. "Don't put pressure on either country . . . . I believe you've got your work cut out for you."

In a transcript of a second phone conversation between the two that Anderson described in a radio broadcast, Reagan tells Haig: "In those talks with the British , if it's helpful at all, why, don't hold back on making me the bad guy and insisting on restraint if that's necessary."

He also asked Haig: "Incidentally, that submarine of theirs, do you think it's apt to go ahead with retribution and sink anything within 200 miles, and would that be enough to vindicate them?"

Reagan also reportedly expressed surprise at the belated British reaction to Argentina's invasion of the Falklands, observing to Haig that a British submarine had been in the area for some time, supposedly monitoring Argentine military movements.