Hundreds of Rohingya migrants from Myanmar broke out of a detention centre in northern Malaysia on Wednesday with six killed on a highway as they escaped, authorities said.

Many Rohingya arrive in Malaysia by boat after enduring harrowing, months-long sea journeys. Those that are caught are often sent to detention centres, which rights groups say are typically overcrowded and filthy.

A total of 528 people from the Muslim minority group fled a centre in Kedah state at 4:30 am (2030 GMT Tuesday), the country's immigration chief Khairul Dzaimee Daud said.

"A total of 362 detainees have been re-arrested. The search for the remaining detainees is continuing," he said in a statement. 

They broke through a door and barriers at the temporary immigration centre, he added.

Six of the detainees were killed as they sought to cross a highway after escaping, said Penang state police chief Mohamad Shuhaily Mohamad Zain.

Those killed were two adult men, two adult women, one girl and one boy, he said.

Police, other agencies and the public are hunting for the detainees still missing.

Relatively affluent, Muslim-majority Malaysia is a key destination for Rohingya fleeing persecution in their predominantly Buddhist homeland or refugee camps in Bangladesh.

More than 100,000 Rohingya live on the margins of society in the country, working illegally in construction and other low-paid jobs.