Western Australia will close its borders to reduce the spread of coronavirus, Premier Mark McGowan announced in a press conference today.

The announcement comes as 30 new cases of coronavirus in WA were confirmed overnight, bringing the state total to 120.

“Western Australia is now in a war – the type of war we have never seen before,” said McGowan. He's urged all interstate visitors to cancel their holidays to WA.

From 1.30pm Tuesday, anyone arriving from interstate, whether residents or visitors, will be required to self-isolate for 14 days. The strict new border controls will apply to all road, rail, air and sea access points (exemptions will apply for essential services and workers). It follows similar measures introduced in South Australia, Tasmania and the Northern Territory.

Several hotels will soon become self-isolation zones for those "who have difficulty self-isolating or who won’t self-isolate", McGowan said. Tourist destination Rottnest Island is also being investigated as a quarantine zone.