A regional conference is under way in the Thai capital Bangkok to discuss possible solutions to the South East Asia migrant crisis.
The talks include member states from the Association of South East Asian Nations (Asean) as well as representatives from the US and the UN.
Bangladesh and Myanmar have seen an exodus of people fleeing south by boat to Thailand, Indonesia and Malaysia.
Thousands are thought to be stranded at sea in abandoned boats.
Most are economic migrants from Bangladesh and Rohingya Muslims fleeing persecution in Myanmar - also known as Burma.
In his opening remarks, Thailand's Foreign Minister Tanasak Patimapragorn said "the influx of irregular migrants... has reached alarming levels" and an urgent and united response was needed.
"The root causes that motivated these people to leave must also be addressed," he added in comments apparently directed at Myanmar and Bangladesh.
Friday's talks include representatives from 17 countries affected by "irregular migration in the Indian Ocean" - Australia, Bangladesh, Cambodia, India, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Vietnam, Thailand, New Zealand, Papua New Guinea, Sri Lanka, Pakistan, Afghanistan and Iran.
The US, Japan and Switzerland have sent observers and there are officials from the UN refugee agency, the UN Office on Drugs and Crime and the International Organization for Migration.
However, correspondents say many of those attending are not ministerial-level and the talks are unlikely to produce a binding agreement or even a plan of action.
Myanmar, which denies the Rohingya citizenship, making them effectively stateless, has played down any hopes of an agreement.
"We are going there only to discuss the regional crisis which all of the Asean countries are facing," Htein Lin, head of Myanmar's delegation, told Reuters news agency.
The crisis began earlier this year when Thailand cracked down on overland migrant routes, forcing people smugglers to use sea routes instead.
Most countries are unwilling take in the migrants, fearing that by accepting them they will encourage more to make the journey.
Malaysia and Indonesia have agreed to stop towing boats out to sea and to give temporary shelter to those who have landed. Thailand has only said it will stop rejecting the boats.