WA govt proposes 'anywhere, anytime' knife search laws

Western Australian police could be given greater powers to stop and search citizens without reasonable suspicion under proposed laws designed to combat knife crime.

Officers would be legally permitted to use hand-held metal detectors to scan people for hidden weapons in so-called Knife Wanding Areas designated by police.

A positive scan would provide officers with reasonable suspicion to conduct further and more thorough searches.

Any person who refuses to let officers carry out a wanding scan on them or refuses to produce an object found during the search, could be jailed for up to one year and fined $12,000.

Premier Roger Cook says his government is serious about tackling the threat of knife crime to better protect Western Australians.

"We've seen the devastating outcomes - both here and in other parts of the country - that can eventuate when people choose to act outside the law," he said on Thursday.

"I make absolutely no apology for targeting those thugs who think it's acceptable to go into public in a public place with a knife."

If the laws pass parliament, WA's entertainment precincts in Northbridge, Fremantle, Hillarys, Scarborough and Mandurah would become permanent Knife Wanding Areas, enabling officers to search people who enter them for hidden knives and other dangerous items.

Under the proposal, senior police ranked inspector or above would be empowered to declare KWAs in any public place such as shopping centres, bus stops, train stations, and sporting, community or entertainment events.

Short-term KWAs would be enforced for up to 12 hours, with the potential to be renewed as operationally required.

The changes also include a new edged weapon offence, which increases penalties for the illegal possession of bladed weapons to a maximum of three years imprisonment, with a fine of $36,000.

Police Minister Paul Papalia said a designated KWA could be up to three square kilometres in size and would "create an area big enough to scan anyone going into (Perth's city centre) for a major threat".

"You will not know when or where the police have declared a knife wandering area, they could be anywhere, anytime," he said.

The minister said the knife scanning was non-invasive and linked it to random breath testing of drivers' blood alcohol levels.

"It is a small number of people who have taken to carrying knives and as a consequence there has been some very high-profile, very concerning and frightening events," he said.

"This is about making sure people understand that if you carry a knife in public you may be targeted."

People found to be carrying a knife with a legitimate reason would be protected from prosecution but possession for self-defence is not considered a lawful excuse.

Anyone caught selling an edged weapon to a person under the age of 18 would also face a higher penalty of up to three years behind bars, with a $36,000 fine, under the legislation.

Stricter penalties for prohibited weapons, such as ballistic knives and knuckle knives, will also be introduced to parliament, increasing the penalty from three years imprisonment and a $36,000 fine to five years jail and a fine of $60,000.