SYDNEY, March 3 (CNA) - Australia will extend its year-long international border closure by at least three months to mid-June, continuing the country's self-imposed isolation to keep the coronavirus at bay.

Health Minister Greg Hunt said health officials had advised the government "the COVID-19 situation overseas continues to pose an unacceptable public health risk to Australia, including the emergence of more highly transmissible variants".

As a result, strict border controls will continue until Jun 17, he said on Tuesday.

Australia closed its international border early in the pandemic, shutting out most non-citizens except in special circumstances.

Caps were also imposed on the number of Australians permitted to return each week, leaving tens of thousands stranded overseas.

Travellers allowed into the country must spend thousands of dollars to complete 14 days in hotel quarantine on arrival.

Australia has been relatively successful in containing the spread of COVID-19, with just under 29,000 cases recorded in a population of 25 million and few virus restrictions now in place.