The Australian government is defending its record for detecting boats carrying asylum seekers into its waters.
A boat carrying 77 people arrived off Christmas Island on Thursday night. They are believed to be from Afghanistan.
The ABC reports a mobile phone was used to ring emergency services and advise Australian authorities of their arrival in Australian waters.
HMAS Wollongong intercepted the boat about 12 nautical miles off Christmas Island.
It is the 74th asylum boat to arrive this year, but Border Protection Minister Brendan O'Connor says no boat has reached the mainland.