Mohd Zawawi Abdullah, provincial director for the Malaysian Maritime Enforcement Agency, said in a statement that two boats and one aircraft were sent out on Sunday to scour an area of more than 100 square nautical miles.
"We have relayed information to other rescue agencies and local fishing communities and will also inform the Thai authorities ... to assist in the search," Zawawi said
Abdullah confirmed that the 27-year-old named Nor Hossain was detained for questioning after he swam to shore on Langkawi.
"Based on the information from the police, the illegal Rohingya migrant had jumped off the boat that had 24 other people and that he was the only one who managed to swim to the shore safely," Zawawi said.
Malaysia's coastguard earlier said at least 25 people had tried to swim to shore late on Saturday when their boat ran into difficulty near the island.
Last month, about 270 Rohingya were detained on arrival in Langkawi.
Malaysia has long been a common destination for persecuted Rohingya refugees after escaping a 2017 military crackdown in Myanmar and, more recently, refugee camps in Bangladesh. Malaysia has recently turned away boats and detained hundreds of Rohingya, saying it cannot take in more refugees because its economy is struggling as a result of the COVID-19 pandemic.
Last month, Malaysian Prime Minister Muhyiddin Yassin said the country could not take in any more Rohingya, citing a struggling economy battered by the coronavirus pandemic.
Malaysia has stepped up maritime patrols since the outbreak of the coronavirus to stop Rohingya boats from landing. Although some have made it ashore, many boats have been turned back, sparking anger from rights groups.