A Indonesion ship searching for a missing passenger plane detected a large object off the coast of Sulawesi on Monday but it has not been confirmed whether or not the object is the plane.

"We suspect that it was a metal object 1,050 metres under the sea off Mamuju. It could not be confirmed yet whether it was the Adam Air plane," Tony Syaiful, the spokesman of the navy's Eastern Fleet, told Jakarta-based Radio Elshinta.

The plane, a Beoing 727-400 budget Adam Air carrier carring 102 people went missing during bad weather on New Year's Day halfway through a flight between the central island of Java and the island of Sulawesi to the northeast.

As well as the bad weather hampering the search, a disaster in communications led to reports by officials that the wreckage had been discovered on a remote mountain in West Sulawesi and that there were some survivors. The reports later turned out to be false.

The plane disappeared less than three days after a ferry with more than 600 aboard capsized and sank off Java.

Indonesian President Susilo Bambang Yudhoyono has called for an investigation into what went wrong in both cases as well as a general probe into the state of Indonesia's transport system.