Authorities intercepted a boat carrying suspected refugees in Australian waters, the immigration minister said on Wednesday.
It was the fifth boatload of suspected asylum seekers to enter Australian territorial waters in two months.
Immigration Minister Chris Evans said the vessel, carrying 35 passengers and five crew, was spotted by a surveillance plane late on Tuesday and intercepted near Ashmore Island, off Australia's northwest shore.
The nationalities and intentions of the group were not yet known. Home Affairs Minister Bob Debus said the boat is believed to have traveled from Sri Lanka.
Australia has long been a destination for people from poor, often war-torn countries hoping to start a new life, and many have come from Iraq or Afghanistan in recent years. They typically fly to Indonesia before continuing to Australia aboard cramped, barely seaworthy boats.
The group will be taken to Christmas Island, where they will be detained while their status is determined. Under government regulations, those not qualifying for asylum will be returned to their country of origin.
Evan suggested the boat may have been part of a people-smuggling syndicate, and said the smugglers were trying to avoid interception by changing their tactics and the size of their boats. "Ongoing conflicts in countries such as Iraq, Afghanistan and Sri Lanka have seen thousands of displaced people seeking refuge around the world, and the people smugglers are exploiting these people at their most vulnerable times," Evans told reporters. "There is also increasing evidence that people smugglers are recruiting customers in source countries."
In July, the government eased some of Australia's mandatory detention policies for asylum seekers, but retained the practice for refugees who could pose a security threat. Children can no longer be detained, and all asylum seekers are given access to lawyers at the government's expense.