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The move will also remove the exemption from the 14-day self-isolation that most interstate fly-in, fly-out workers were granted.
Under the hard border rules people trying to cross the state's eastern border will be likely turned back.
There are exemptions relating to vital functions such as health and emergency services workers; transport, freight and logistics; and specialist skills not available in WA.
There will also be exemptions for FIFO workers and their families, however, strict 14-day self-isolation measures will need to be followed when they first enter the state.
Of WA's 45,000 FIFO workers, about 3500 are from interstate.
WA premier Mark McGowan said implementing a hard border was a drastic step but also sensible and workable.
"We are living in extraordinary times, it's something we have all never experienced before," he said.
"These new harder border closures essentially mean we will be turning WA into its own island, within an island - our own country.
"A number of specific exemptions will be implemented to ensure our state can continue to operate and function. We need to keep our state working."
McGowan's move to require all FIFO workers arriving from interstate to quarantine for 14 days has drawn support from BHP.
The company has already relocated about 300 of its interstate FIFO workers to WA.
BHP WA Iron Ore asset president Tim Day said the miner was well prepared for the stronger border controls and would continue to implement measures to protect the health and safety of its people, their families and the communities in which it operates.
"We are all in this together and we will continue to work with the many local suppliers and contracting partners we have in WA to ensure we support local jobs and local businesses," he said.
"The mining sector is a critical part of the state and national economy and we are committed to working with government and playing our part to help keep our industry operating safely during this difficult time."
Measures implemented across BHP's WA iron ore sites also include amending rosters to minimise travel to the Pilbara, restricting FIFO workers from entering the townships of Newman and Port Hedland, increasing the use of charter flights and increasing the use of health screening such as temperature checks at mine sites and airports.
Other miners are also making similar moves to limit FIFO travel.
On the FIFO front from midnight April 4 Queensland will make interstate FIFO workers quarantine for 14 days unless they are in critical roles.
