Boris Johnson's official spokesperson has urged the International Olympic Committee to make a "definitive decision" on postponing this summer's Games in Tokyo.
The IOC said on Sunday night it was now looking at contingency scenarios to tackle the coronavirus pandemic, which included postponing the event, but that it would take up to four weeks to make a final decision.
That approach has been widely criticised, with the Canadian Olympic and Paralympic committees already announcing they will not send teams to Tokyo.
The British Government has now spoken out on the matter and wants the IOC to act decisively as a matter of urgency to give clarity to competitors.
The Prime Minister's official spokesman said: "Athletes are facing significant uncertainty in the current environment. Their health and safety, alongside that of sports fans and officials due to work at the Games must be absolutely paramount.
"We want the International Olympic Committee to make a definitive decision soon to bring clarity to all of those involved.
"The Sports Minister Nigel Huddleston set out yesterday that the IOC should be seriously considering postponing the Games."
A statement from the Tokyo 2020 organisers on Monday afternoon reiterated that discussions would be finalised in the next four weeks, adding: "Our thoughts are with all those affected by this crisis, and we will continue to prioritise the safety of athletes, spectators and all other Games participants."
A leading figure on the British Olympic Association's athletes' commission has described IOC president Thomas Bach as arrogant and stubborn over its approach to the pandemic.
Callum Skinner, a 2016 Olympic cycling champion, was scathing about Bach in a social media post on Monday morning.
"IOC president Thomas Bach's stubbornness and arrogance has spectacularly failed in this instance and he has weakened the Olympic movement," Skinner wrote on Twitter.
"This isn't the first time he has put his own motives above the athletes and the movement."
Skinner's post went on to praise those national Olympic committees and international sports federations which have already expressed opposition to the Games going ahead as scheduled.
UK Sport, the BOA and the British Paralympic Association will hold a conference call with chief executives and performance directors of the summer Olympic and Paralympic sports on Tuesday to discuss the impact the Covid-19 on the ability of competitors to train.
GB Taekwondo announced on Monday it had suspended all centralised elite training and was closing the national base in Manchester until further notice.
Canadian officials have said they will not send athletes to the Tokyo Games and have "urgently" called for the event to be postponed until 2021.
Japanese prime minister Shinzo Abe told his country's parliament on Monday that a postponement would be unavoidable if the event cannot be held in a complete way because of the Covid-19 pandemic.
The Olympics has never been postponed or cancelled during peacetime.
Almost 13,000 people worldwide have been killed by Covid-19, according to the latest WHO figures, with cases in 187 countries, areas or territories.
The Australian Olympic Committee (AOC) has told its athletes to prepare for the Games being held "in the northern summer of 2021".
Australian team chef de mission for Tokyo Ian Chesterman said in a statement: "It's clear the Games can't be held in July.
"Our athletes have been magnificent in their positive attitude to training and preparing, but the stress and uncertainty has been extremely challenging for them.
"They have also shouldered the burden of concern for their peers around the world.
"While there will still be much to work out as a result of this change, the timing will allow athletes from around the world to properly prepare with the hope the coronavirus crisis will be under control."
The Azerbaijan Grand Prix, which had been due to take place on June 7, has been postponed due to the outbreak.
It is the eighth Formula One race so far to be affected by the pandemic.
Former England striker turned broadcaster Gary Lineker tweeted that he is self-isolating after his son George displayed symptoms of the virus.
Lineker Sr wrote: "In self isolation as @GeorgeLineker has symptoms.
"They're not the regular ones, but complete loss of sense of taste and smell. Odd these have not been pointed out much.
"Been nearly a week and has spent time at mine. I've been vigilant, hand washing/distancing but isolation it is."
Meanwhile, Australia's rugby league competition, the NRL, has suspended its season. Matches, played behind closed doors, had continued to take place until Sunday.
Newcastle have put back their scheduled return to training until next month in line with the Premier League's revised suspension.
The Magpies were initially due to head back to their Darsley Park headquarters on March 30, but have set a new provisional date in April which could yet alter as the club continues to monitor the situation.
In the meantime, the players continue to work on individually-tailored training programmes at home with data being fed automatically to the club's sports science team, while staff remain in regular touch.