Despite President Carter's avowed desire to ease Cold War-era travel restrictions, the State Department has denied a visa to an Australian Communist labor leader who had been admitted to the United States during the final months of the Ford adminsitration.

State Department officials said yesterday that Jack Mundey, a former president of the 40,000-member Builders Laborers' Federation in Australia, was denied a visa last month because his itinerary included talks with some labor groups.

He was admitted to the United States for 10 days in November because the purpose of that visit was to meet with enviromental groups, including speaking at the ilnternational congress of the World Wildlife Fund in San Francisco, the officials said.

Mundey, who heads an Australian insititute devoted to forging bonds between environmentalists and trade unionists, ran afoul of a long-standing State Department rule against granting visas to Communist labor officials who want to come to the United States to talk with labor groups or about labor matters.

Last year, in a case involving a Soviet trade union delegation, the State Department acknowledged that the AFL-CIO, which bitterly opposes communism in the labor movement, has a virtual veto over visits by Communist labor officials.

Department officials said they knew of no specific protest by the AFL-CIO to Mundey's visa request, but one official said the department is aware of the "attitudes of the mainstream of American labor" and takes them into consideration in reviewing visa requests.

Under the McCarran Act of the 1950s, members of Communist parties are denied visas unless waivers are granted. Though there have been exceptions, the general rule is to bar waivers to labor officials seeking to discuss labor matters, officials said.

Acknowledging that Mundey's message probably would have been the same last month as it was in November, one official observed that the rationale for the two decisions involved a "talmudic distinction." The policy itself was consistent, he said.

In response to a question during his Feb. 23 press conference about his policy of supporting human rights in the Soviet Union and elsewhere, President Carter noted that the United States signed the Helsinki agreement, which includes a call for wider East-West exchanges, and said:

"We are, ourselves, culpable in some ways for not giving people adequate right to move around our country, or restricting unnecessarily, in my opinion, visitation to this country by those who disagree with us politically."

The Associated Press reported last month that the administration is reviewing the McCarran Act and quoted an unnamed administration official as saying: "It would be inconsistent for this country to limit the free movement of people, ideas and information across international frontiers while President Carter goes on pressing governments of the Soviet bloc and others to respect those human rights as set forth in the Helsinki agreement."

Mundey was granted transit rights through the United States and is in Canada, according to Richard Grossman, coordinator of the Washington-based Environmentalists for Full Employment, which, with the World Wildlife Fund and Friends of the Earth, was trying to arrange speaking engagements for him last month.

One of the labor groups he was scheduled to address was a labor-management institute at the University of California.

Mundey's union in Australia pioneered in use of so-called "green bans" under which unions refused to work on projects they considered to be environmentally damaging. It claims to have halted work on 42 projects involving $4 billion worth of construction.