A boat carrying 83 suspected asylum seekers was intercepted on Saturday off Australia's northwest coast after being spotted from the air by a military patrol plane, officials said.
The vessel was spotted around midnight about 80 nautical miles south of Ashmore Island and initially appeared to be in distress, said Home Affairs Minister Brendan O'Connor.
"The people on board the vessel are safe and have indicated that they wish to come to Australia," he said. "Initial indications suggest 83 passengers and four crew are on board."
It is the 20th illegal vessel to be stopped this year.
A small boat carrying seven suspected refugees was found in the same area on Monday.
And Indonesian officials intercepted a wooden boat carrying 56 Afghan migrants on Friday as it made its way to Australia, with one claiming he had paid 7,000 dollars to a Jakarta middleman for the trip.
Over 1,000 would-be refugees have landed in Australia this year, and the government has warned that there were thousands more waiting in Indonesia, a key staging post for people smugglers.
More than 1,000 migrants from countries including Myanmar, Afghanistan, Iraq, Sri Lanka and Pakistan have been caught there since November last year.
O'Connor said international unrest was to blame for the surge in boat numbers, and not a softer refugee policy, as claimed by the conservative opposition.
"Situations around the world mean that large numbers of displaced persons are looking for settlement in wealthy, developed nations like Australia and can be targeted by, and fall prey to, people smugglers," O'Connor said.
"People smuggling is a world-wide problem and Australia is committed to working closely with our neighbours to address the issue," he added.
The latest group, whose nationality is unknown, were to be taken to Christmas Island, home to Australia's largest immigration detention centre, for health, security and identity checks, O'Connor said.