Canada is set to drop its vaccine requirement for people entering the country while Japan will also loosen border curbs as the World Health Organisation warns about a decline in the monitoring of coronavirus variants.

Prime Minister Justin Trudeau has signed off on Canada dropping the vaccine requirement at the end of September, an official familiar with the matter told the Associated Press on Thursday.

Canada, like the United States, requires foreign citizens to be vaccinated when entering the country.

No change in the mandate is expected in the US in the near term.

Unvaccinated foreign travellers who are allowed to enter Canada are currently subject to mandatory arrival tests and a 14-day quarantine.

The official said that Trudeau has agreed to let a cabinet order enforcing mandatory COVID-19 vaccination requirements at the border expire on September 30.

Trudeau's government is still deciding whether to maintain the requirement for passengers to wear face masks on trains and planes.

Unvaccinated professional athletes like major league baseball players would be allowed to play in Toronto in the play-offs should the Blue Jays make the post-season.

They currently are not allowed to cross the border into Canada.

Japan's strict border restrictions will be loosened next month, the prime minister announced on Thursday, allowing tourists to easily enter for the first time since the start of the pandemic.

In a news conference at the foot of Central Park in New York, Prime Minister Fumio Kishida said independent tourists would again be welcomed as of October 11, not just those travelling with authorised groups.

A cap on the number of tourists will also be lifted, as will new visa requirements that were imposed in response to the pandemic.

The global decline in monitoring for the coronavirus means that discovering new variants is becoming more difficult, the WHO said in Geneva on Thursday.

The virus was still circulating "at an incredibly intense level around the world," COVID-19 expert Maria Van Kerkhove said.

She expressed concern at the way the virus was continuing to mutate.

"This is something we are deeply concerned about. Our ability to track variants and subvariants around the world is diminishing because surveillance is declining," Von Kerkhove said.

WHO head Tedros Adhanom Ghebreyesus emphasised again that while the end of the pandemic was in sight, strategies had to be maintained to combat it.

Speaking via video link from New York, where he is attending the United Nations General Assembly, Ghebreyesus said that the world was "just beginning to glimpse the light at the end of the tunnel" but he added: "We're not there yet.

"Being able to see the end does not mean we are at the end," he said.

While the weekly number of fatalities linked to the virus was declining, the number, at almost 10,000, was still too high, Tedros said.