The coronavirus-delayed Tokyo Olympics could cost $1.9 billion more than its original budget of $13 billion, a 15 per cent increase, a report said on November 29.

The Olympics organisers will formally decide the increased budget for the Games as early as mid-December after communicating with the Japanese government and the host city Tokyo, the Yomiuri Shimbun reported, citing unnamed Olympic sources.

The 2020 Games were pushed back a year as Covid-19 spread around the globe, and are now scheduled to open on July 23, 2021.

But the delay has thrown up a plethora of new costs, from rebooking venues and transport to retaining the huge organising committee staff.

With many countries experiencing second or even third waves of infection, there have been doubts about whether the event can be staged, but organisers and Olympic officials insist it can be done.

The extra 200 billion yen ($1.9 billion) on the pre-coronavirus estimate of 1.35 trillion yen comes despite organisers last month slashing $280 million by cutting everything from staffing to pyrotechnics, but the new figure does not include costs of the coronavirus-related measures, the report said.

Officials expect the virus-linked measures will be paid by the Japanese government, it said.

IOC chairman Thomas Bach has instisted there will be fans.