Two Indonesian fighter jets were scrambled on Wednesday to force a prop-driven Australian light plane to the ground after its pilots initially refused several orders to land, the Indonesian military has said.

The comments by air force spokesman Major-General Fuad Basya significantly escalate the seriousness of the case against the two pilots, Richard Wayne Maclean of South Australia and Graeme Paul Jacklin of Brisbane.

The Australian plane on the tarmac at Manado's Sam Ratulangi airport.

"Initially they did not want to land and kept flying," General Fuad told Fairfax Media. "However after being forced again and again they agreed to land at the Sam Ratulangi airport in Manado."

Under Article 414 of the 2009 aviation law, violating Indonesian airspace carries a maximum sentence of five years in jail and a 2 billion rupiah ($200,000) fine.