Japan could push its Winter Olympics bid back four years to 2034 after corruption scandals related to the Tokyo Games, the country's Olympic chief has warned. 

The northern city of Sapporo has been aiming to host the 2030 Games but Japanese Olympic Committee president Yasuhiro Yamashita told reporters that it would be "difficult to move ahead without gaining people's understanding". 

His comments come as prosecutors investigate allegations of bribery and bid-rigging at the 2020 Summer Games in Tokyo, which were postponed to 2021 because of the pandemic. 

Local media reported Yamashita as saying that he would discuss the bid with Sapporo's mayor, who won re-election on Sunday ahead of two anti-Olympic candidates. 

Yamashita said the talks would include the option of bidding to host the Games in 2034 instead of 2030. 

He added that the mayoral election had "made it clear that a lot of people in the city have concerns and anxieties" about the bid. 

An exit poll by Jiji news agency found that a majority of voters oppose Sapporo's bid. 

Of 651 voters surveyed after casting their ballots, 53 percent said they opposed hosting the Games, while 27 percent were in favour and 20 percent expressed no opinion. 

The city of Sapporo has already said that it will not hold a public referendum on hosting the Games. 

But it announced in December that it would stop actively promoting the bid and hold a nationwide poll to gauge support. 

Alternative host candidates for the 2030 Games have been dropping out, with Salt Lake City now expressing a preference for 2034 instead. 

Other bids have been withdrawn, including those from Vancouver and Barcelona-Zaragoza. 

Sweden announced in February that it was considering throwing its hat in the ring for 2030.