Tens of thousands of people flocked to a cauldron with the Olympic flame in northeastern Japan over the weekend despite concerns about the coronavirus pandemic.

The flame arrived in Japan to a scaled-down welcoming ceremony on Friday as doubts grew over whether the 2020 Tokyo Olympics will go ahead on schedule as the deadly virus causes chaos around the world.

The pandemic has already shredded the global sports calendar, with top sports leagues suspended and major tournaments postponed.

More than 50,000 people on Saturday queued to watch the flame displayed at Sendai station in Miyagi, chosen as part of the "Recovery Olympics" to showcase the region's revival after the 2011 earthquake, tsunami and nuclear meltdown.

Some had to stay in a 500-metre (1,650-foot) queue for several hours, local media said.

Many of them wore masks as they took pictures with the cherry blossom-shaped cauldron.

"I queued for three hours but watching the Olympic flame was greatly encouraging," a 70-year-old woman told public broadcaster NHK.

But organisers, concerned about the bigger-than-expected gathering, have warned the viewing event could be suspended if a crowd becomes "extremely dense", local media reported.

The nationwide torch relay begins on March 26, starting from the J-Village sports complex in Fukushima that was used as a base for workers during the 2011 nuclear disaster.

But organisers have been forced to scale back the relay, closing daily ceremonies to the public and urging spectators to "avoid forming crowds" along the route.