MELBOURNE, Nov 28 (Reuters) - Health officials in Australia"s most populous state have begun urgent testing after two people who arrived on a flight from southern Africa overnight tested positive to the coronavirus, raising concerns that a newly detected, highly infectious strain has arrived in the country. Australia imposed new restrictions on Saturday on people who have been to nine southern African countries, as the new Omicron variant raises concerns about another wave of the pandemic. read more "Urgent genomic sequencing is underway to determine if they have been infected by the new omicron...variant of concern," the health department of New South Wales said in a release. The passengers arrived in Sydney on Saturday evening and were transported to a hotel for 14 days of quarantine. Other passengers on the flight may be considered close contacts and will need to get tested immediately and isolate for 14 days, and compliance checks will be undertaken, NSW Health said. Australia early this month eased its international border restrictions for the first time during the pandemic, allowing fully vaccinated residents to return to the country without quarantine after higher vaccination levels. Australia had largely stamped out infections for most of this year until an outbreak of the highly infectious Delta variant in late June spread rapidly across its east. About 205,000 cases and 1,985 deaths have been recorded so far, lower than many other countries in the developed world.