A vessel carrying 79 passengers and two crew was spotted north of Christmas Island overnight by an RAAF surveillance plane and was later assisted by HMAS Pirie.
The second carrying 44 passengers and three crew was intercepted east of the island early on Sunday morning by HMAS Larrakia.
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On Saturday a boat with 15 passengers and one crew member was found west of Ashmore Islands off the West Australian coast.
"Border Protection Command will now make arrangements for the passengers to be transferred to Christmas Island, where they will
undergo initial checks and their reasons for travel will be established," Home Affairs minister Brendan O'Connor said in a statement.
The latest arrivals take to four the number of boats that have arrived since the federal government conceded it could not get legislation aimed at reviving its Malaysian asylum seeker swap deal through the parliament.
The first boat, which had 51 passengers and four crew on board, was intercepted by Australian customs vessels near Scott Reef, about 250km northwest of Broome, on October 18.
