A Bali court has sentenced an Australian man found guilty of stealing a pair of sunglasses to three months and 15 days in jail.

Key points: Thomas William Harman faced a possible five years' jail

Thomas William Harman faced a possible five years' jail Perth man said he was "very happy" with the sentence

Perth man said he was "very happy" with the sentence Prosecutors has demanded 6 months' prison

Thomas William Harman, 31, has only five days left of his sentence with time already served, lawyers said.

Harman was found guilty of stealing the designer label sunglasses from a duty-free shop at Bali's international airport, prior to flying to Perth.

He faced a maximum five years' jail for the crime.

The glasses were being sold in the shop for about $400. ( Supplied )

The Perth man, who has been in Bali's Kerobokan prison, expressed his relief at the sentence.

"Very happy, thank you, it's been great," Harman said outside court.

"Once again I apologise to the people of Indonesia for the crime."

The glasses, that were being sold in the shop for about $400, were tended to the court as evidence.

Prosecutors argued Harman was caught on CCTV taking the glasses which showed his intention to steal, and demanded he be jailed for six months.

But the panel of three judges was more lenient.

Mr Harman has already spent three months in jail. ( ABC News )

The judges said they did not impose the six-month jail term demanded by the prosecutor because Harman was polite before the court, admitted the crime, was remorseful, and promised never to do it again.

Harman's defence lawyer, Erwin Siregar, said the Australian had apologised, expressed remorse and offered to pay double the amount to the shop.

"If this thing happened in America I would just be going to the police, I would pay the bill, my client is out," Mr Siregar said after the sentencing.

"Three months and 15 days is OK."