HANOI, Vietnam (AP) _ Vietnam has freed a political prisoner who was imprisoned 16 years for trying to publish newspaper articles critical of the Communist government.

The release of Quach Vinh Nien apparently was the result of U.S. and Australian demands that Vietnam improve its human rights record.

Nien joined his wife and daughter in Australia on May 11 after being freed from prison earlier this year, the Australian foreign minister, Gareth Evans, said in a statement today.

Nien was arrested in 1978 and sentenced in 1980 to life in prison on charges of anti-government activity and disloyalty. His wife and daughter are Australian.

Meanwhile, a Vietnamese intellectual jailed for advocating democratic reforms, Doan Viet Hoat, was reported ill from kidney stones and a hunger strike, Human Rights Watch-Asia said in a statement.

Hoat has been denied visitors, including his wife, since he began to refuse food in early April to protest his treatement at an isolated jungle camp, the New York-based rights group said.

Hoat stopped eating after his jailers shackled his arms and legs when he and four other prisoners objected to performing hard labor, it said.

A government spokesman had no immediate comment on the allegations.

Hoat, who is being held in solitary confinement in Thanh Hoa province, 93 miles south of Hanoi, is a professor of English literature who studied in the United States.

He was sentenced in July to 15 years in prison on charges of attempting to overthrow the government by publishing four issues of a clandestine newsletter, Freedom Forum, which urged Vietnam's leaders to adopt democratic reforms.

The Clinton administration lifted the 19-year U.S. economic embargo against Vietnam in February, saying human rights would become increasingly important as the two nations try to normalize relations.

That same month the U.S. State Department issued a report charging rights violations. U.S. Assistant Secretary of State Winston Lord is likely to raise the charges when he visits Hanoi late next month.

An Australian delegation is to visit Vietnam in July to examine the country's human rights record.