The “test, trace, protect” system is launching in Wales on Monday.
It will see the close contacts of people who have tested positive for coronavirus asked to self-isolate for 14 days.
Similar systems are under way in England, Scotland and Northern Ireland.
It comes on what Health Minister Vaughan Gething called a “big day” with a “significant easing” of the lockdown, so people could see others from another household.
He said he was “proud to be taking choices that are in accordance with our scientific advice.”
Under the new rules, people in Wales from two different households will be able to meet outdoors. But they will need to stay in their local area – within five miles as a “general rule” – and remain two metres apart.
But Mr Gething added that ultimately, it was for ministers to decide and take responsibility.
“I hope the people of Wales understand this really is about how we keep Wales safe,” he told BBC Wales.
About 600 staff have been recruited so far for the “test, trace, protect” system, as it has been called in Wales.
Up to 1,000 people will be needed as it is expanded.
Anyone with symptoms of the virus can apply for a home test kit or make an appointment at a drive-through test centre.
An online portal was also made available at the weekend for anyone who has symptoms in Wales to book an appointment.
Capacity has increased in recent weeks, with labs able to test 9,000 samples a day.
NHS Wales chief executive Dr Andrew Goodall, when asked last week if 600 staff would be enough on Monday, said: “We’ll need to get up to a number of 1,000, but we don’t need that from the first day.”
“That’s a progressive number that we need to put in place, but we have 600 available and in place,” he added.
Existing staff with public health experience have been deployed, as more are recruited.
“We’ll expect that number to keep increasing and certainly in line with the demand we expect,” he said.
Mr Gething said it was key to be able to contract trace to keep people safe and for the Welsh Government to be able to look ahead to further easing of lockdown restrictions.
“By the next review period we’ll have more evidence about what we’re able to do, and that will give us more confidence about considering further adjustments,” he told BBC Wales.
“We’ve had really clear advice from our scientists, that they want that test, trace, protect system to be in place, and to be robust, before further significant adjustments from lockdown are taken. That’s the approach we’re taking.”
Some local health boards and local authorities have been trialling the new system in recent weeks.
It is anticipated that as many as 20,000 tests a day might be needed in Wales, as part of the UK-wide testing programme.
A greater demand on the system is expected in the autumn and winter, when more people are likely to present with possible symptoms.
Dr Goodall added the testing approach was part of a “set of measures that we need to put in place.”
He said: “It’s really important to make sure that we still have the ongoing efforts on the ground – the need for example to make sure that we have good infection control both in our hospitals and our care homes, and those mechanisms continue.”