A Canadian man who conspired to import about $237 million worth of drugs into Australia inside a road roller has been sentenced to life in prison.

Mark Clermont, 36, acted out of greed when he arrived from Canada on a short-term visa in April 2010, Acting Judge Anthony Garling said in the Downing Centre District Court.

Clermont set up a front company in Sydney with co-accused Mathieu Horobjowsky, a 35-year-old Canadian, called Clermont & Horobjowsky Pty Ltd and began importing floorboards, tractors and forklifts in a bid to look legitimate.

In September 2012, a 20-tonne road roller, with methamphetamine and cocaine hidden in its barrel, arrived in Australia.

Judge Garling said that although Customs conducted tests on the roller, which indicated drugs may be present, they were not prepared to deconstruct it so it was allowed in.

Drugs haul valued at $237 million

A month later, Horobjowsky left the operation and Clermont established another company which was set up at a warehouse in Warriewood on Sydney's northern beaches and purchased equipment to allow the drugs to be removed.

Judge Garling said the conspiracy may have succeeded if it was not for the persistence of Australian Federal Police.

Blocks of methamphetamine were hidden inside the road roller. ( Australian Federal Police )

"When discovered by the AFP the drugs were packed ready to be taken from the premises," Judge Garling said.

The AFP carried out a search warrant at a storage unit at Warriewood in northern Sydney in 2012, where officers found the 20-tonne road roller, dismantling equipment and 13 sports bags containing the methamphetamine and cocaine.

During the operation a total of 235 kilograms of methamphetamine, worth an estimated street value of up to $174 million, and 115 kilograms of cocaine, worth an estimated street value of up to $63 million were seized along with approximately $150,000 in cash.

Clermont was sentenced to life imprisonment with a non-parole period of 20 years while Horobjowsky received a maximum 20 years with a non-parole period of 13 years.

AAP