One of his close contacts in Perth tested positive for Covid-19 on Friday in the first case of community transmission of the disease in the state in 12 months, prompting the lockdown order, McGowan said.
The second was his close contact in Perth, Western Australia Premier Mark McGowan said in a televised news conference, where he announced the lockdown.
Mr McGowan said test results are forthcoming after contact tracers uncovered 337 contacts linked to the initial local case.
Anyone in New Zealand who had been in Perth or Peel since 17 April should check the locations of interest page on the Ministry of Health website, and the * a href="http://urldefense.com/v3/__https://scanmail.trustwave.com/?c=15517&d=4e6D4JipNvfnLBGeil7OwoZcLz6WP3jiPf29dloR7g&u=https*3a*2f*2fwww*2ehealthywa*2ewa*2egov*2eau*2fArticles*2fA*5fE*2fCoronavirus*2fLocations-visited-by-confirmed-cases__;JSUlJSUlJSUlJSUl!LBk0ZmAmG_H4m2o!8Z4QYP-juo8t4JZaWYVRPx22yiIZkaZdDBUe02xtv3CFC5xqrivWigTA4gixH1y_LaEthHEa$" *Western Australia Department of Health site.
Before Covid-19 brought New Zealand's tourism industry to its knees, it was the country's biggest export industry, with Australians accounting for about 40% of the global visitors.More news: National advisory committee recommends AstraZeneca vaccine for people 30 and older
The Anzac Day dawn services in the lockdown areas will be cancelled and people must wear masks when leaving their homes.
The positive test result was received on Saturday afternoon, updating information given hours earlier by Premier Mark McGowan that there were no new local cases.
The announcement follows an outbreak in Perth's hotel quarantine system, with a Victorian man testing positive in Melbourne today after completing 14 days of quarantine at a WA hotel.
It is understood he acquired the virus inside hotel quarantine at the Mercure Hotel.
"This is an important and timely reminder to all of us that this pandemic is not over", he said.More news: Russia: Doctors denied access to ‘very weak’ Alexei Navalny
Mr McGowan said he remained deeply frustrated Canberra had not supplanted the hotel quarantine framework with permanent facilities and suggested commonwealth facilities at Curtin Air Base near Derby could hold 1500 people and Christmas Island could also be used. Returned travelers, except from New Zealand, have to undergo two weeks of mandatory hotel quarantine at their own expense.
"Even if you have not visited one of the locations, if you have symptoms, get tested and self-isolate until you get your result", WA Health said.
Authorities fear guests who tested negative at the end of their NSW hotel quarantine and were allowed to leave could have already been exposed to the virus, raising the risk of it spreading in the community.
Just after midnight, South Australia shut its border to people from Perth or Peel aside from permitted and essential travellers.
A snap three-day lockdown is underway in metropolitan Perth and the Peel region, due to the initial locally acquired cases.More news: Family: 15-year-old girl shot, killed by police in Columbus, Ohio
The NT has also declared Perth and the Peel region COVID-19 hotspots.