Australian leader gets his first political rebuff

Australian Prime Minister Bob Hawke has run head-on into his first domestic political setback since he took office two months ago. The subject: an attempt to update the Australian constitution, if possible in time for the Australian bicentennial celebrations in 1988.

The forum: a four-day meeting last week of the Australian Constitutional Convention.

The debacle: the convention, which includes representatives of the federal and state parliaments, failed to achieve essential cross-party concensus in a debate wracked with political acrimony. Without such consensus, there is little likelihood of success in piloting changes through the complicated revision process, including a nationwide referendum.

The initial cause of the partisanship was a decision of the Queensland and Tasmanian premiers to stack their delegations with conservative politicians. The two conservative premiers also met before the convention to plan their tactics. These were to attack the federal Labor government at every opportunity and to resist any proposal which could alter the constitutional balance in favor of the federal government.

In the divided atmosphere, Mr. Hawke was unable to persuade the conference to vote for the national Parliament to have a fixed term of three or four years. And the federal Liberals, the main opposition party, backed away from the idea of simultaneous elections for the federal Senate and House of Representatives.

Mr. Hawke left the convention blasting at the ''new conservative alliance'' which he said was ''obsessed with preserving the past for a minority of Australians.'' He insisted that irrespective of the outcome of the convention, he would put forward a series of proposals for constitutional changes in July or August, including the scheme for a fixed-term Parliament which enjoys over 70 percent public support in polls at the moment.