The British government was on Thursday expected to extend a nationwide lockdown for another three weeks, amid signs the coronavirus outbreak is peaking but also warnings of more deaths to come.

Cars pass a sign on the side of the A30 road in Old Basing, near Basingstoke, west of London on April 16, 2020, reading "Perhaps we took our NHS for Granted...." as life in Britain continues during the nationwide lockdown to combat the novel coronavirus pandemic. (Photo: AFP)

Foreign Secretary Dominic Raab, who is standing in for Prime Minister Boris Johnson as he recuperates after spending a week in hospital with COVID-19, met with ministers and officials to finalise the plans.

An announcement is due later but the government has already said that, with the death toll approaching 13,000 and still rising, now is not the time to rescind the stay-at-home order imposed on March 23.

"It is too early to make a change," Health Secretary Matt Hancock told BBC television on Thursday.

"Whilst we've seen a flattening of the number of cases, and thankfully a flattening of the number of deaths, that hasn't started to come down yet. And as far as I'm concerned that is still far too high."

He said the vast majority of Britons had followed rules not to go out except for exercise and to buy essential items.

"I don't want to put all of that good effort to waste," said Hancock, who himself has also had coronavirus but recovered quickly.

"Because if we just released all the measures then this virus would run rampant once again, and we can't let that happen."

He did not say how long the lockdown would continue, but the law states that the measures must be reviewed every 21 days.

England's chief medical officer, Chris Whitty, said Wednesday that the outbreak was peaking but warned the numbers of deaths would keep rising.

Health ministry figures show 12,868 people in hospital in Britain have so far died, making it one of the worst affected countries in the global outbreak.