Bangkok: Thai police have downplayed a probe into more than 50 officers transferred over suspected links to human trafficking networks, saying the transfers were ‘hstandard operating procedure’ and that most of the officers were suspected only of negligence.

Southeast Asia is being hit by a wave of migrants arriving in Thailand, Malaysia and Indonesia, part of a regional human trafficking crisis driven by conflict, persecution and poverty.

Police Lieutenant General Prawut Thawornsiri, spokesman for the Royal Thai Police, said on Monday the transfers of the policemen were part of normal procedure and that most did not have direct links to human traffickers. Rather, they had been negligent in the detection of human trafficking camps and gangs in southern Thailand.

‘This is normal procedure to move them out for investigation,’ Prawut told Reuters in an interview. ‘We are conducting an internal investigation and it should be done in one month.

‘The accusation against them is failure in their duty to respond and their duty to care.’

Malaysia detained more than one thousand Rohingya migrants from Myanmar and Bangladeshis earlier on Monday, a day after Indonesian authorities rescued more than 500 stranded off the coast of the country's western tip.

In Thailand, authorities are questioning more than 100 migrants near the country's border with Malaysia to determine whether they were victims of human trafficking.

Thai Prime Minister Prayuth Chan-ocha ordered a clean up of suspected human trafficking camps around the country last week after 33 bodies, believed to be of migrants from Myanmar and Bangladesh, were found in shallow graves in the south of the country, near Malaysia.

Last year, Thailand was downgraded to the U.S. State Department's lowest category - or Tier 3 - in its annual Trafficking in Persons Report, which assesses how governments around the world have performed in fighting human trafficking.

Prawut said Thailand has known about human trafficking within its borders for years but that, before the downgrade to Tier 3, officials considered human trafficking to be a small criminal business.

‘Before Tier 3 everybody thought that this was a small case. Everybody knew about the camps for Rohingya. Locals made profit to take care of the Rohingya on their way to Malaysia. It was seen as a small business, like tourism, but lately these guys got rich so it has become a big business.’

An estimated 25,000 Rohingyas and Bangladeshis boarded people-smugglers' boats in the first three months of this year, twice as many in the same period of 2014, the UN refugee agency UNHCR said on Friday.