CANBERRA, Australia (AP) _ Prime Minister John Howard moved closer Tuesday to calling an early election, warning there was no alternative if the Senate tried to change his Aboriginal land rights legislation.

The government maintains two High Court rulings allow Aborigines to lay claim to more than 79 percent of Australia's total land mass _ a description Aboriginal leaders say is wildly misleading.

A bill being debated in the Senate aims to restrict Aborigines' ability to claim limited rights to land covered by ranching leases issued by the government.

On Tuesday, independent Sen. Brian Harradine, who holds the key vote, detailed 56 amendments to Howard's bill that he said were not negotiable.

Howard has repeatedly said he will not consider changes to the bill. He told a government coalition party meeting Tuesday that an early election was the only option if the Senate refused to pass the legislation unchanged.

Howard needs Harradine's support, but Harradine has said the prime minister will not get it.

The senator has proposed, instead, that Aborigines be allowed to keep their right to negotiate, but not veto, plans for development on their tribal lands. This goes directly against the government's bill.

Under the constitution, the prime minister can dissolve both houses and hold new elections if the Senate twice rejects government legislation with an intervening three-month break.

The Labor opposition and other critics, however, have warned that an election triggered by this bill would ensure a divisive campaign fought on race issues.