Exclusive: 'They're carrying lethal weapons and they need to be in full control' - cops poised for random drug testing

The mother of a man who was shot dead by police welcomes random drug and alcohol testing for officers, saying "they're carrying lethal weapons and they need to be in full control".

To improve safety, police will soon test all staff involved in critical incidents for drugs and alcohol. Source: 1 NEWS

Stephen Jon Bellingham, 37, was fatally shot by police during a 2007 incident in Stanmore Road in Christchurch.

Police will begin random drug and alcohol tests on officers next year.

The Independent Police Conduct Authority has been calling for drug testing after major incidents like the shootings of Stephen Wallace and Stephen Bellingham, since 2009.

"They're carrying lethal weapons and they need to be in full control of those weapons," Mr Bellingham's mother Maria said.

Deputy Commissioner Mike Clement told ONE News around 500 personnel will be tested next year as well as any officers involved in "critical" events like car chases that led to crashes or shootings.

Until now testing could only be carried out by consent.

"I certainly have no evidence that there's a problem," Mr Clement said. 

"But that's not to say we shouldn't have a robust policy that deals with the issue of safety at work in a drug and alcohol sense."

Authority chairman, Judge David Carruthers, says it'll avoid speculation and rumours when critical incidents occur.

"If we get rid of those suspicions then that's a large ingredient of rumour and speculation which is removed."

A drug testing agency spoken to by ONE News estimates it'll cost less than $100,000 a year.