An IT contractor has been jailed for stealing tens of thousands of dollars in gold bars and coins and smuggling them out of the Perth Mint, in order to fund his lavish lifestyle and "shower his partner with gifts".

Joseph Charles Viola, 29, pleaded guilty in the District Court to six charges of stealing the items, worth a total of $55,000 and including a limited edition Kimberley sunrise coin, between February and April 2016.

He was caught after an audit was conducted by the Mint's security, which revealed five gold bars and eight gold coins were missing from a vault.

CCTV footage was then reviewed which showed Viola taking a gold coin from a vault, hiding it in a computer tower and then transferring the coin into his trouser pocket, before leaving the Mint at the end of his shift.

Further investigations revealed that on a number of occasions, Viola had sold other coins and gold bars from the Mint to a gold bullion dealer across the road, and had received payments in excess of $50,000.

They included a 10-ounce gold cast bar valued at more than $15,500 and the 2-ounce Kimberley Sunrise coin which was worth almost $7,000.

Viola stole a 10-ounce gold cast bar valued at more than $15,000. ( Supplied: Perth Mint )

Viola's lawyer, Graeme Allen told the court his client had committed the offences to fund the lifestyle he believed his then-fiancee wanted.

"The demands from that relationship led him to make the unfortunate choice to steal gold from the Mint," he said.

"Quite simply, Mr Viola wasn't coping with the fact that his relationship was failing and he also wasn't coping with the fact that he couldn't afford to maintain a lifestyle which was necessary for that relationship to be maintained."

Mr Allen urged Judge John Prior to impose a suspended jail term, describing Viola as "a very fragile person" who had "a complicated psychological background".

But state prosecutor Sarah Keogh said only an immediate jail term was appropriate, describing the offences as "planned, premeditated and relatively sophisticated".

Security fooled under smuggling scam

Ms Keogh said Viola used his role as a technician to get access to all areas of the Mint and had convinced security staff to change their protocols so that computer hard drives were not x-rayed, by falsely claiming it would damage data.

He also fended off one security officer's attempt to examine a computer tower by telling the officer it was sensitive and would be damaged if inspected properly.

The man smuggled the gold past Perth Mint's security by hiding it inside computers. ( Perth Mint )

Judge Prior accepted that the offences were out of character, but said they involved some planning and premeditation and were "a significant breach of trust".

He said the thefts were "motivated by greed" to fund his lifestyle, noting that Viola "felt obliged to look after his (then) partner and shower her with gifts and dinners".

The offences had impacted on the operations of the Perth Mint and the morale of its staff, the judge said. Statements from two employees to the court outlined the distress and anxiety they had suffered before Viola had been caught, after their honesty and integrity had been questioned.

Judge Prior sentenced Viola to two years' jail.

He will have to serve half the term before he can be released.