Prime Minister Scott Morrison has said Australia will review its plans to reopen borders to skilled migrants and students from December 1 after the country reported its first cases of the Omicron coronavirus variant, Reuters reports.

Two people who arrived in Sydney from southern Africa have tested positive for the newly identified variant as officials ordered 14-day quarantine for citizens returning from nine African countries.

Morrison said "it is a bit too early" to reinstate two-week mandatory hotel quarantine for foreign travellers, urging people to remain calm as data had not yet fully determined the severity, transmissibility and vaccine resistance of the Omicron strain.