* Australia's re-opening in doubt after Omicron cases
* Asian markets, oil prices recover a little
* Still unclear if Omicron causes more severe disease -WHO
* Britain plans G7 meet of health ministers on Mon
* Biden to provide U.S. response update
SYDNEY, Nov 29 (Reuters) - The global spread of the Omicron variant of coronavirus has brought new cases in Australia, Denmark https://www.reuters.com/article/health-coronavirus-denmark/denmark-registers-omicron-variant-in-two-travelers-from-south-africa-idUSC7N2R000D, France https://www.reuters.com/world/europe/omicron-variant-likely-be-circulating-france-health-minister-2021-11-28 and the Netherlands, prompting nations to reconsider plans for international travel as they scramble to avert an outbreak.
News of the variant triggered alarm and a sell-off last week in financial markets, as countries clamped on new curbs for fear it could resist vaccinations and upend a nascent economic re-opening after a two-year global pandemic.
The World Health Organisation (WHO) warned that deciding the severity level of Omicron, identified first in South Africa, could take "days to several weeks" in the absence of information that its symptoms differed from those of other variants.
Asian markets and oil prices regained some composure as investors settled in for a few weeks of uncertainty as they wait for more details.
Australia will review plans https://www.reuters.com/world/asia-pacific/australias-reopening-plans-doubt-after-omicron-cases-2021-11-28 to re-open to skilled migrants and students from Dec. 1, Prime Minister Scott Morrison said on Monday, while adding it was a "bit too early" to reinstate two-week mandatory hotel quarantine for foreign travellers.
"So we just take this one step at a time, get the best information, make calm, sensible decisions," Morrison told broadcaster Nine News.
A national security panel will meet later in the day to assess border relaxations due from Wednesday, he added, with leaders of all states and territories to meet by Tuesday.
He called for calm as the severity, transmissibility and vaccine resistance of Omicron had not been determined, echoing remarks by the WHO, which dubbed it a "variant of concern".
Potentially more contagious https://www.reuters.com/world/how-worried-should-we-be-about-omicron-variant-2021-11-27 than previous variants, Omicron has now been detected in Australia, Belgium, Botswana, Britain, Canada, Denmark, France, Germany, Hong Kong, Israel, Italy, the Netherlands and South Africa.
Symptoms of Omicron were so far mild and could be treated at home, a South African doctor, one of the first to suspect a different variant, has said https://www.reuters.com/world/africa/safrican-doctor-says-patients-with-omicron-variant-have-very-mild-symptoms-2021-11-28.
Countries from Indonesia to Saudi Arabia have imposed travel curbs for visitors from southern Africa to limit the spread.
Singapore has deferred the start of vaccinated travel lanes with some Middle Eastern countries, such as Qatar, Saudi Arabia and the United Arab Emirates, given "their proximity as transport nodes to the affected countries", its health ministry said.
Britain said it would call an urgent meeting of G7 health ministers on Monday.
In the most far-reaching effort against the variant, Israel is to ban the entry of foreigners and re-introduce counter-terrorism phone-tracking technology, it has said https://www.reuters.com/world/middle-east/israel-ban-entry-foreigners-all-countries-over-omicron-2021-11-27.
South Africa has denounced the measures https://www.reuters.com/world/africa/safrica-says-it-is-being-punished-early-covid-variant-detection-2021-11-27 as unfair and potentially harmful to the economy, saying it was being punished for its scientific ability to identify variants early.
"The prohibition of travel is not informed by science, nor will it be effective in preventing the spread of this variant," President Cyril Ramaphosa said on Sunday.
"The only thing (it) ... will do is to further damage the economies of the affected countries and undermine their ability to respond."
President Joe Biden will give an update on the variant and the U.S. response on Monday, the White House said in a statement.
It will take about two weeks to get definitive information about the transmissibility and other features of Omicron, Dr. Anthony Fauci, the top U.S. infectious diseases official, has told Biden, it added.
Fauci believes existing vaccines "are likely to provide a degree of protection against severe cases of COVID", the White House said. (Reporting by Renju Jose in Sydney and Chen Lin in Singapore and Reuters bureaus; Writing by Himani Sarkar; Editing by Clarence Fernandez)