Prime Minister Tony Abbott says he won't criticise countries that are turning back asylum-seeker boats to stop people smuggling.
Thousands of Rohingya from Burma and Bangladeshi migrants are feared stranded at sea with Indonesia, Malaysia and Thailand turning away their rickety boats.
Mr Abbott said on Sunday he was not critical of efforts made by other nations to stop people smuggling in the region.
"I don't apologise in any way for the action that Australia has taken to preserve safety at sea by turning boats around where necessary," he said.
"And if other countries choose to do that, frankly that is almost certainly absolutely necessary if the scourge of people smuggling is to be beaten."
If that meant taking "more vigorous" action on the high seas or closer to Burma, so be it, he said.
Violent clashes and 'maritime ping-pong' as nations turn Rohingya away
A boat crammed with migrants was towed out to sea by the Thai navy and then held up by Malaysian vessels on Saturday, the latest round of "maritime ping-pong" by Asian states determined not to let asylum seekers come ashore.
The United Nations has called on countries around the Andaman Sea not to push back the thousands of desperate Bangladeshis and Rohingya Muslims from Myanmar now stranded in rickety boats, and to rescue them instead.
"We're not seeing any such moves from any governments in the region even though we're calling on the international community to take action because people are dying," said Jeffrey Savage, who works with the UNHCR refugee agency in Indonesia, where some 1,400 migrants have landed over the past week.
Nearly 800 came ashore near Langsa in Indonesia's Aceh province on Friday, many with stories of a gruelling voyage that included push-backs from the Malaysian and Indonesian coasts.
Mahmud Rafiq, a 21-year-old Rohingya man who left Myanmar a month ago, recounted how an Indonesian navy ship given them food and medicine before towing their boat to Malaysian waters, where they were again stopped, given supplies and taken right back.
While adrift at sea, he said, the Rohingya and Bangladeshi migrants had fought fiercely over dwindling supplies of food.
"We had very little food, and we agreed that we would leave it for the women and children," said Rafiq. "Then they started hitting us. They took the food. They pushed many of us overboard. They beat us and attacked us with knives. I was hit with a wooden plank on the head and on my legs."
According to the ABC, survivors are saying seven people were killed during clashes for supplies, and another seven children died during the voyage. Further claims unable to be verified are that 100-200 people drowned while at sea.
An estimated 25,000 Bangladeshis and Rohingya boarded smugglers' boats in the first three months of this year, twice as many as in the same period of 2014, the UNHCR has said.
A clampdown by Thailand's military junta has made a well-trodden trafficking route into Malaysia - one of Southeast Asia's wealthiest economies - too risky for criminals who prey on Rohingya fleeing persecution in Buddhist-majority Myanmar and on impoverished Bangladeshis looking for work.
In response, many people-smugglers appear to have abandoned their boats in the Andaman Sea, leaving thousands thirsty, hungry and sick, and without fuel for their vessels' engines.
One of those boats was towed away from the Thai coast by Thailand's navy on Saturday, only to be intercepted off the Malaysian coast.
Reuters journalist on a speedboat taken from southern Thailand's coast said that the people aboard had little shelter from the blazing sun. Some of the women were crying, and some passengers waved their arms and shouted.
The International Organization for Migration has criticised Southeast Asian governments for playing "maritime ping-pong" with the migrants and endangering their lives.
US Secretary of State John Kerry on Friday urged Thailand to considering sheltering the homeless Rohingya and called on its neighbours not to send the migrants back out to sea.
Responding to the pressure, Malaysian Prime Minister Najib Razak said his country already had 120,000 illegal migrants from Myanmar and the "humanitarian catastrophe" was a global issue to be resolved by the international community.
"We allow some of them to land and provide humanitarian aid to them but Malaysia must not be burdened with this problem as there are thousands more waiting to flee from their region," Najib told the state news agency Bernama on Saturday.
The United Nations said this week that the deadly pattern of migration across the Bay of Bengal would continue unless Myanmar ended discrimination.
Most of Myanmar's 1.1 million Rohingya Muslims are stateless and live in apartheid-like conditions. Almost 140,000 were displaced in clashes with ethnic Rakhine Buddhists in 2012.
Myanmar terms the Rohingya "Bengalis", a name most Rohingya reject because it implies they are immigrants from neighbouring Bangladesh despite having lived in Myanmar for generations.
Thailand is hosting talks on May 29 for 15 countries to discuss the crisis.
Myanmar had not received an invitation to the meeting and would not attend if the word Rohingya was used, Zaw Htay, a senior official from the president's office, said on Saturday.
"We haven't received any formal invitation from Thailand officially yet," he said in an emailed response to questions.
"And another thing, if they use the term 'Rohingya' we won't take part in it since we don't recognise this term. The Myanmar government has been protesting against the use of it all along."
In a routine note to Congress, US President Barack Obama said the United States, while not curtailing engagement with Myanmar as it introduces democratic reforms after decades of military rule, would maintain some sanctions on the country.
White House spokesman Eric Schultz said on Friday that Washington continued to raise its concerns with Myanmar over the migrants "because of dire humanitarian and economic situations they face at home out of fear of ethnic and religious violence."