Vanuatu's deputy prime minister Joe Natuman had pleaded guilty to charges of conspiracy to pervert the course of justice.
Mr Natuman was accused of trying to stop a police team from investigating high-ranking officers accused of mutiny when he was prime minister in 2014.
The Supreme Court case stemmed from a complaint made by another former prime minister, Moana Carcasses.
He accused Mr Natuman of pressuring the police chief at the time to suspend investigations into allegations of mutiny in the police force.
Following the complaint Mr Natuman said he acted in the national interests by trying to resolve the impasse in the force.
Now that he has pleaded guilty, the deputy prime minister will be sentenced on 16 March.
It's not yet clear what the implications are for Mr Natuman's political career.
But he would be compelled to resign if he receives a custodial sentence of two years or more.