Health Secretary Matt Hancock has cited asymptomatic people getting coronavirus tests as the reason for mass shortages.
Demand for testing has soared over the past few weeks, with many getting an error message when trying to book a test or being asked to travel hundreds of miles to get one.
Matt Hancock today blamed asymptomatic people for shortages while speaking on the Kay Burley programme, claiming that around 25% of people getting tested do not have any symptoms.
"We have seen an increase in demand including from people who are not eligible for tests, people who don't have symptoms," he said.
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"You are eligible for a test if you have symptoms of coronavirus or if you have a very specific reason otherwise. We have seen an increase, and about 25% of people who are coming forward don't have symptoms and aren't eligible".
Though the figures on asymptomatic cases of coronavirus cases are not clear, some studies have shown that up to 80% of cases can be totally asymptomatic - meaning the person shows no symptoms but can pass the virus on.
Researchers in South Korea - whose study found 30% of cases to be asymptomatic - found that these patients still carried the virus in high amounts.
The head of testing at Whitehall's Test and Trace operation previously cited laboratory processing rather than asymptomatic testers as the reason for testing delays, saying they have reached a "critical pinch-point".
Mr Hancock admitted it could take weeks for the testing problem to be fixed.
Labour, meanwhile, has accused government ministers of "failing to get even the basics right" and "blaming everybody but themselves".
Rachel Reeves, the shadow Cabinet Office minister, told Sky News: "This is a government who promised a world-beating system. Frankly, at the moment, we would just like one that works and we don't even have that."