Australia on Monday abruptly halted plans to reopen its international borders to skilled workers and students, an eleventh-hour decision prompted by concerns over the Covid-19 Omicron variant.
After an emergency security meeting, Prime Minister Scott Morrison said the much-heralded December 1 reopening will be delayed at least two weeks.
Australia's borders have been closed to most non-citizens for more than 20 months, causing labour shortages and pummelling the vital tourist industry.
Morrison described the delay as "a necessary and temporary decision" based on medical advice.Australia has so far detected five cases of the Omicron variant.
"The temporary pause will ensure Australia can gather the information we need to better understand the Omicron variant," he said.
Morrison cited new concerns about "the efficacy of the vaccine, the range of illness, including if it may generate more mild symptoms, and the level of transmission."
A plan to open the border to visitors from Japan and South Korea on December 1 is also now on hold.
Australia has had some of the world's toughest and longest-lasting border restrictions during the pandemic, thanks to a slow vaccine rollout.
The conservative government had opened the border to Australians, permanent residents and Singaporeans, but not the estimated 1.4 million skilled workers who live in the country, who were barred from reentering if they left.
Monday's delay will also cause worry in the country's hard-hit education sector.
According to Universities Australia, an industry group, 130,000 international students remain outside the country.