OTTAWA -- The federal government is now warning Canadians against all non-essential international travel in the face of the rapidly spreading Omicron variant of COVID-19.

"To those who were planning to travel I say very clearly, now is not the time to travel," Health Minister Jean-Yves Duclos said Wednesday at a news conference in Ottawa.

"The rapid spread of the Omicron variant on a global scale makes us fear the worst."

Duclos said the highly transmissible variant is now spreading in Canadian communities, and just about everywhere else in the world. He said that people who leave the country risk spreading the virus, and getting stranded abroad.

The new advisory takes a stronger stance than the one published shortly after the emergence of the Omicron variant, urging Canadians to be aware that travel to an area with Omicron could hamper their ability to return to Canada.

"We know that this may sound very drastic," Duclos said. "But we must avoid overloading our hospital system and our health-care workers."

Ministers warned more measures at the border could still be on the way, and did not rule out the possibility of reinstating the requirement for travellers who leave the country for less than 72 hours to complete a molecular COVID-19 test in order to re-enter Canada.

Currently, Canada has banned all foreign nationals who have been in 10 specific African countries in the last 14 days from entering the country to offset the threat of importing Omicron cases. That policy should be re-examined, chief public health officer Dr. Theresa Tam said Wednesday. Duclos hinted the government may "clarify" that policy soon.

Duclos would not offer advice on domestic travel, adding that any travel restrictions within Canada will come from provincial governments.

The announcement came after Prime Minister Justin Trudeau spoke with provincial and territorial premiers Tuesday evening to discuss how to respond to Omicron.

Ottawa has agreed to send shipments of booster doses and rapid tests to provinces and territories to quickly ramp up vaccination campaigns to combat the virus at home.

Trudeau and the premiers also discussed potential domestic measures to stop community spread.

Meanwhile Tam has advised against all mass gatherings, even for people who are fully vaccinated.

"At this point in time, what we know is that even if you have two doses, there's a possibility you could be infected and spread to others," Tam said Wednesday.

Earlier Wednesday, Trudeau warned that people should be careful as they finish making their Christmas plans this year in light of the new variant.

Finance Minister Chrystia Freeland dedicated $4.5 billion in Tuesday's fiscal update to respond to the Omicron variant.

The government has also set aside $1.7 billion to buy and distribute rapid tests to the provinces, and $2 billion for drugs to treat people who have been infected.

"I know that the rising threat Omicron poses is not something any of us want to be dealing with, especially now, just before the holidays," Freeland said Wednesday.