Premier Mark McGowan has reinstated tougher border measures for the Northern Territory, Queensland and the Australian Capital Territory.

From 6pm tonight they will move to “very low risk” jurisdictions, and travellers will be required to self-quarantine for 14 days and undergo COVID-19 testing.

It comes after a Perth woman in her 50s tested positive to COVID-19, plunging the Perth and Peel region into tougher restrictions.

The woman’s husband, who travelled with her to NSW, has tested negative to the virus.

A number of public exposure sites have been listed, including Burbridge School in Koondoola and Connolly Primary School in Connolly.

The two schools will be closed on Monday to allow for extensive cleaning.

Anyone who visited an exposure site is required to get tested and follow isolation requirements.

Authorities are concerned the woman may have contracted the deadly Delta variant of the virus, however tests are yet to confirm it.

The Premier said acting quickly was the most effective way to “crush and kill” the virus.

“Unfortunately the situation around the country is very concerning,” he said.

“This is a safe and sensible response.”

Masks will be mandatory indoors and on public transport in the Perth and Peel regions for the next three days.

The two square metre rule has been reintroduced and events are limited to a maximum of 150 people.

186 people linked to the NT gold mine outbreak will be required to quarantine for 14 days and get tested.

173 have been contacted by WA Health and of those 61 have returned negative test results.

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(Photo: Matt Jelonek/Getty Images)