POLICE have charged a chef at a resort island off Cairns who allegedly took delivery of an M4 rifle, a gun barrel extension and laser pointer ordered on the internet.

Officers are puzzled over how a military-style assault rifle bypassed strict Australian Customs screening and landed in the hands of a chef working on Green Island.

Detectives raided the 52-year-old's Green Island Resort room and uncovered the banned M4 carbine rifle, a gun barrel extension and laser pointer on Monday afternoon.

Cairns CIB Detective sergeant Brad McLeish said it appeared the weapon had been ordered online. "(Resort management) had their suspicions one of their employees had been importing gun parts," he said.

"The packages had been arriving on the island.

"Another employee entered the room of the offender and sighted what he thought was an assault-style rifle."

The man, who had been living and working on the far north Queensland island, was charged with two counts of unlawful possession of a Category D weapon and one count of unlawful possession of a restricted item.

"We arrived (on Green Island) at about 7.30pm," Det-Sgt McLeish said. "He was arrested, charged and released on bail (and) not to return to the island."

Det-Sgt McLeish said the weapon was incapable of firing and police had not found ammunition during their search.

The managing director of resort owner Quicksilver Group, Tony Baker, said his staff prompted police to execute the search warrant.

The M4 carbine firearm is commonly used by the US military.

The 52-year-old is expected to appear in the Cairns Magistrates Court on August 8.

Originally published as Chef charged over M4 rifle find