Travellers will need a negative test from within 48 hours of departure to get into Australia, a move labelled "disproportionate and simply unacceptable" by China.
Monitoring the international border will prove a crucial part of Covid management moving forward after eight cases of the XBB.1.5 variant were detected in Australia, after it was first reported in the US last month.
Kirby Institute associate professor Stuart Turville said it was too early to know if the Omicron-descendant would bring more serious illness and hospitalisations.
"There is a lot of hysteria on social media saying this is the next big one," Dr Turville told AAP.
"Until the data is in hand, it's just crystal ball gazing."
The federal government had earlier hit back at China after a foreign ministry spokeswoman said the measure wasn't science-based and was instead being used for political purposes.
"Every country will make its own decisions ... this is a modest measure," Emergency Management Minister Murray Watt told reporters on Wednesday.
"I don't think that's a drastic step, and it's identical to the steps being taken by more than a dozen other countries."
One country that won't follow suit is New Zealand, which opted against the negative test requirement after determining Chinese visitors wouldn't significantly lift the overall caseload.
Deputy Liberal leader Sussan Ley continued calls for Labor to explain its rationale.
"It's not about (China), it's about what we do with our international borders," she told Nine radio.
"This government is not following medical advice, so they need to explain what advice they are following and ... the rationale for their decision."
