The Indonesian air force has used two of its new Russian-built fighter jets to intercept an Australian plane that had violated its airspace.

A spokesman for the Indonesian air force, First Air Marshal Hadi Tjahjanto, said the civilian prop-driven plane was detected on Wednesday morning by radar off southern Maluku in eastern Indonesia.

“The plane violated the official path around Saumlaki,” he said, referring to a town in Maluku.

“Because they’re civilians, the case will be under the authority of airport authorities.

“For now they can’t fly, we’re waiting until the results of this investigation.”

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The aircraft, a Beechcraft 95, had departed from Darwin and was travelling to Cebu in the Philippines.

The plane was forced to come down in Manado, in North Sulawesi, after two Sukhoi fighter jets were scrambled from Makassar airbase to intercept it.

The captain’s name was Graeme Paul Jacklin of Brisbane, and his co-pilot was South Australian businessman Richard Wayne MacLean.

The pair were quizzed by military investigators before being handed over to airport authorities for further questioning, spokesman Hadi Cahyanto said.

“They don’t have a letter of clearance allowing them to enter Indonesian airspace,” he said.

“But because they are civilians, not military, we have handed them over to the airport authorities for investigation.”

The men have been questioned and their papers checked but it is unclear whether they will face any charges.

According to Fairfax Media, violating Indonesian airspace carries a maximum sentence of five years in jail and a 2 billion rupiah ($200,000) fine.

Mr Maclean’s wife, Kaye, told Fairfax that her husband “ferries planes all around the world … it’s his job”.

“I think there’s a misunderstanding,” she said.

– with AAP