A GROUP of Australians working overseas, led by 1999 Young Australian of the Year Bryan Gaensler, has written to Prime Minister John Howard to slam his asylum seekers policy.

Dr Gaensler painted a picture of embarrassment for Australians abroad, saying Mr Howard's actions vilified refugees.

The letter accused the Prime Minister of framing the debate to give legitimacy to intolerance and urged him to move beyond populism and conduct national affairs to promote a forward-thinking country.

"We are deeply concerned that Australia's international standing as an open and tolerant nation has been compromised," the letter said.

"As ambassadors for our country, we have found it difficult to justify to our overseas colleagues the Australian government's recent decisions in this regard."

The letter was last night delivered to Mr Howard, Governor-General Peter Hollingworth, Greens Senator Bob Brown, Opposition Leader Simon Crean and Australian Democrats Leader Natasha Stott Despoja.

It was also copied as a letter to the editor of major newspapers.

"Furthermore, we strongly object to the Government's use of language that de-humanises and vilifies refugees trying to escape persecution," the letter said.

"We feel that, as prime minister, you have a responsibility to encourage Australian citizens to overcome their fears and uncertainties about the significant changes that are currently taking place in the international sphere.

"Instead, we believe that your Government has framed the debate in a way that gives legitimacy to intolerance in the general community.

"We ask you to move beyond populism and to conduct Australia's affairs in a way that reflect our status as a forward-thinking nation."

Australia must comply with its international treaty obligations, be a responsible world humanitarian citizen and boost its humanitarian refugee program, the letter said.

"We call on the Australian Government to put an end to mandatory detention and to inhumane treatment of asylum seekers," the letter said.

"We care deeply about Australia's role and future direction, and strongly entreat you to re-visit these issues."

The letter was signed by Dr Gaensler, the 1999 Young Australian of the Year who is now a fellow at the Harvard-Smithsonian Center for Astrophysics at Harvard University in the United States.

It was also signed by more than 130 Australians working and studying overseas, in the US, Europe, Latin America, Asia and New Zealand, including scientists, bankers and other professionals.

Dr Gaensler said the group remained strongly connected with what was occurring in Australia.