Malaysia is a favored destination for the group from mostly Buddhist Myanmar, who have long complained of persecution, as it is a Muslim-majority country that already has a sizeable Rohingya diaspora.

But authorities have strengthened maritime patrols in an effort to stop the illegal arrival of Rohingya due to fears they could be infected with the virus, and a boat was turned away by the navy last week. 

Another boatload of Rohingya did make it to shore on the island of Langkawi in early April, and officials said the pair detained last week was believed to have been involved in that case. 

In another incident earlier this month, 60 Rohingya died on a crammed boat stranded in the Bay of Bengal for two months, which survivors said had been turned away from Thailand and Malaysia. 

The latest arrests were brothers aged 31 and 34, officials said.

"Authorities seized a notebook detailing information on the money collected from their human-smuggling business related to the April 5 arrival of 202 Rohingya Muslims in Langkawi," said Zulinda Ramly, deputy director with the Malaysian Maritime Enforcement Agency.

Each migrant paid 15,000 ringgit ($3,400) to be brought into Malaysia, she said.

The coastguard is hunting other syndicate members, Malaysians and foreigners, accused of helping migrants illegally enter the country.

Malaysia's tougher stance in seeking to stop the arrival of boatloads of Rohingya has alarmed rights groups, who fear several other vessels may be at sea between Bangladesh and the Southeast Asian nation.

Rohingya often begin their journeys in Bangladesh, where many of the minority live in overcrowded camps after fleeing a military crackdown in their homeland.