SYDNEY, June 20 (Reuters) - Australians would support responding to a Chinese attack on Taiwan with economic sanctions, arms supplies or using the navy to prevent a blockade, but don't support sending troops, an opinion poll to be released Wednesday finds.

Canberra says it is opposed to any unilateral attempt to change the status quo in Taiwan, while the United States has long stuck to a policy of "strategic ambiguity" over whether it would respond militarily to an attack on the island, which Beijing has refused to rule out.

Prime Minister Anthony Albanese told Asia's top security meeting in June that Australia supports dialogue between the United States and China because a conflict in the Taiwan Strait would be "devastating for the world".

The annual Lowy Institute poll of public attitudes to the world found 82% of those surveyed supported the security alliance with the U.S., although three-quarters also think that means Australia would be drawn into war in Asia.

The prospect of a military conflict between the United States and China over Taiwan was seen as a "critical threat" by 64% of Australians surveyed, worrying twice as many people as two years ago. The top threat cited, by 68% percent of respondents, was cyber attacks from other countries.

Ryan Neelam, director of public opinion at the foreign policy think tank, said the poll showed Australians are "cautious about conflict", but willing to support Taiwan without becoming a ground combatant.

"When it comes to a specific scenario where Taiwan is under military threat and the U.S. is engaged, Australians feel quite forward leaning about taking action to support Taiwan when it comes to accepting refugees, imposing sanctions on Beijing, sending arms and supplies, even getting the navy involved, but that doesn't extend as far as putting boots on the ground," he said.

Eighty percent support accepting Taiwanese refugees, 76% support "imposing economic and diplomatic sanctions on China", 64% support "Australia sending arms and military supplies to the Taiwanese government", and 61% support "using the Australian Navy to help prevent China from imposing a blockade around Taiwan".

Only 42% supported sending "Australian military personnel to Taiwan to help defend it from China".

Eighty-seven percent said they were concerned that China could open a military base in the Pacific islands.

The poll also reflects stabilising ties between Australia and China, who are major trading partners; 56% said resuming diplomatic contact was in the national interest.

Lowy Institute executive director Michael Fullilove said Australian trust levels in China remain "strikingly low", with 15% saying they trusted China to act responsibly in the world, compared with half five years ago.

The poll is based on surveys of 2,000 people in March and 4,000 in April.