Health Secretary Matt Hancock says the government has "a huge amount of work to do" to meet its target 100,000 coronavirus tests a day in the UK.
Mr Hancock said he was not relying on new antibody blood tests to meet the goal, which was announced after criticism of the UK's testing strategy.
"It's got to happen. I've got a plan to get us there, I've set it as a goal and it's what the nation needs," he said.
Labour has called for more details on what kind of tests will be involved.
It came as the Prince of Wales officially opened London's new 4,000 bed NHS Nightingale Hospital via a video link from his Scottish home.
Mr Hancock told BBC Radio 4's Today programme it was possible almost all of the 100,000 tests would be swab tests used to determine whether a person currently had coronavirus.
He said they would also include 500 highly-accurate antibody blood tests - to detect whether someone has already had coronavirus - performed each day by the military's science laboratory at Porton Down.
But other types of antibody blood tests for mass screening had so far failed to meet the required accuracy standard and so would not be relied upon to meet the new goal, he added.
"We've got an awful lot of work to do to make it happen," Mr Hancock said.
The pledge to test 100,000 people a day by the end of the month seems incredible at this point - especially as Matt Hancock has clarified his statements last night to say almost all the tests will be the diagnostic swab tests rather than the antibody test.
After all, it has taken weeks to just get to 10,000 tests being done a day.
Facilities wise, he is planning to use the national Public Health England labs and hospital labs currently being used along with resources at universities, research institutes and private companies.
But this is not really the problem - the hospital labs alone could do 100,000 tests in theory.
The big problem has been the shortage of testing kits and chemicals - he must be confident this supply line will be easing in the coming weeks - as well as the wider introduction of quicker swab testing processes that don't rely on the chemical reagents.
There has been growing pressure from frontline NHS staff for the government to make more swab tests available to medics and their families so key staff who are healthy but currently in self-isolation can return to work.
Mr Hancock said 35,000 NHS staff were currently off work because they or a member of their household had had coronavirus symptoms.
He confirmed patients with suspected coronavirus would be first in line for swab tests, followed by "a whole series of critical workers", including medical staff and their families, social care workers, prison and police officers.
Speaking about his own experience with coronavirus following his diagnosis last week, he told Today: "It was pretty worrying especially on the way down because you know how serious this infection can be.
"But after two days or so which were pretty unpleasant - like having glass in your throat and a cough - thankfully I turned a corner and I've recovered."
Mr Hancock announced a "five-pillar" plan to reach the 100,000 target on Thursday, following days of criticism of the government's record on testing.
This involves increasing the number of swab tests through an expansion of centralised testing facilities and additional partnerships with commercial entities, while also introducing an antibody blood test and surveillance to determine the rate of infection.
Research institutes and universities would be processing increased numbers of tests alongside Public Health England efforts, he said.
However, Prof David McCoy, of Queen Mary University, cautioned that testing was not a "magic bullet".
Figures released on Thursday showed the number of people with the virus who have died in the UK had risen by 569, taking the total to 2,921 as of 17:00 BST on Wednesday - with capacity for 12,799 daily tests in England - although just 10,650 people were tested.
The government's target by mid-April had been to test 25,000 per day.
As of 09:00 on 2 April, 163,194 people in the UK had been tested for the virus, of which 33,718 were confirmed positive.