THE UK has seen the biggest day-on-day rise in the number of coronavirus patient deaths as the government comes under increasing pressure over virus tests.

This afternoon, the Department of Health confirmed that the number of confirmed COVID-19 cases had reached 29,474 as of 9am on April 1 - while as of 5am on March 31, 2,352 patients had died.

The number of patients dying after testing positive for the virus went up by 31 percent since figures were last reported by the government 24 hours ago.

The government is under mounting pressure to ramp up the testing of NHS frontline workers as the opposition say the UK is "lagging" behind other countries.

Today, the Prime Minister's official spokesman said more than 2,000 NHS staff had now been tested, adding: "We're very clear that we want more testing to be carried out, and that we are working with NHS England, Public Health England and others to ensure that happens."

However, Labour's shadow health secretary Jonathan Ashworth called for an explanation on why the UK's Covid-19 testing is lagging behind other countries.

He said: "Germany are testing half a million people a week, yet we still haven't hit the 10,000 a day the Prime Minister promised.

"NHS staff are rightly asking if we've left it too late to buy the kits and chemicals we need, or whether our lab capacity is too overstretched after years of tight budgets."

But some scientists said ramping up testing in the UK will prove difficult for the government.

Stephen Baker, professor of molecular microbiology at the University of Cambridge, said: "There are multiple issues with setting up new diagnostic testing capacity outside of regular diagnostic laboratories.

"This is not an overnight solution. Research laboratories have different approaches, equipment and staff."