A semi-automatic gun which a Queensland officer lost last week has been found, with police believing it was used in a robbery and to hold someone against their will.

The Glock dislodged from an officer's holster about lunchtime on Wednesday in Woodridge, south of Brisbane, and did not turn up despite extensive searches.

A man and a woman, both aged 18, picked up the weapon and then passed it onto another man, Queensland Police allege.

The teens were charged with one count each of unlawful possession of a weapon, unlawful supply of weapons, stealing and a drug-related charge.

Three men were charged with receiving tainted property, including a 24-year-old who was also charged with armed robbery and deprivation of liberty.

A Queensland Police spokeswoman told the ABC it was believed the Glock was used in the robbery and deprivation of liberty offence but did not provide further detail.

They are all due to appear in the Beenleigh Magistrates Court on Monday.

The Queensland Police Union said training procedures should be tightened.

Union president Ian Leavers said there would be an internal investigation.

"Training is a very important issue and the training is of an adequate standard and it just needs to be reinforced," he said.

It is not the first time Queensland Police have lost weapons.

The ABC obtained information under Right to Information legislation in May which showed 39 items were lost last year.

Of the items lost or stolen, 14 were recovered, including two firearms.

In one case of theft, a teenager stole a can of pepper spray, stuffed it into the front of his pants and had to be treated by paramedics for burns.

In a separate incident, an officer on patrol in Yamanto, in Ipswich, lost his bullet-proof vest from the boot of his car.