The threat comes as the country that was praised by Western nations three years ago for ending decades of brutal military rule faces growing criticism over its harsh treatment of Rohingya Muslims.
"We are unlikely to attend . . . we do not accept it if they [Thailand] are inviting us just to ease the pressure they are facing," said Myanmar's presidential office director Zaw Htay.
"The root cause [of the crisis] is increasing human trafficking," he said.
Announcing the summit in Bangkok on May 29, Thailand's Ministry of Foreign Affairs said the crisis demands a multi-nation response with countries working together to address the "root causes as well as the contributing factors along the way".
An estimated 1.3 million Rohingya living in Myanmar's western Rakhine state have been described by the United Nations as among the world's most persecuted people.
They are denied citizenship and other basic rights despite living in Myanmar for generations and have been the target of attacks by Buddhist mobs, forcing a growing exodus to flee the country by making a perilous journey across the Bay of Bengal in people-smuggler boats.
An estimated 25,000 people attempted the journey in the first three months of this year, according to the United Nations, with hundreds killed by starvation, disease or beatings by boat crew members or smugglers.
Myanmar's stand has shattered the notion of co-operation among the 10-member Association of South-East Asian Nations as Thailand, Indonesia and Malaysia engage in what human rights activists describe as a game of "human ping-pong" amid fears for as many as 8000 Rohingya and Bangladeshi migrants and asylum seekers adrift in boats at sea, many of them starving and unwell.
Video and photographs of those on boats show desperate pleas for help from emaciated and distressed Rohingya, many of them women, children and babies.
Up to 22 people died on one boat that Thailand turned away.
The crisis appears to have been caused by a crackdown on people-smuggling networks in Thailand following the discovery of mass graves of Rohingya in people-smuggler camps near Thailand's border with Malaysia.
The crackdown prompted smugglers to abandon their human cargo, leaving thousands stranded at sea or in remote camps.
As the crisis has unfolded Thailand, Malaysia and Indonesia have made it clear those adrift in boats are not welcome on their shores.
Indonesian authorities rescued 797 people on Friday after an overloaded boat sank off its province of Aceh.
In Thailand the Navy discovered 106 Rohingya on an island off the coast of Phang Na, north of the holiday island of Phuket.
Thailand's government has said it will treat any arrivals by boat as illegal immigrants, meaning they could face years languishing in Thai jails.
But Thailand has also raised the possibility of opening Rohingya camps on unpopulated islands but insists it would need assistance from other countries and international agencies to host them.
Similar camps were set up 40 years ago for Vietnamese boat people following the fall of South Vietnam.
The policies of regional nations to shun the boat people adrift has sea has been condemned by the United Nations, the US and other nations.
Australia has agreed to attend the May 29 summit.
US State Department spokesman Jeff Rathke said: "This is an emergency that we believe needs to be addressed with appropriate speed and resolved through a regionally co-ordinated effort to save the lives of thousands of vulnerable migrants and asylum seekers."
The overwhelming inflow of refugees from Bangladesh and Myanmar is enormous.
On May 29 Summit, both countries should be told to stop the Refugee Exodus at once. It is a responsibility that can't be swept under the carpet by Bangladesh and Myanmar. Otherwise a international sea force should set up a blockade just outside the territorial waters of Bangladesh and Myanmar.
Posted by Kurt on May 16, 2015 11:19
Editor Comment:
To do what, Kurt? To turn back boatloads of people who are genuine refugees? Are you a heartless Australian?