A scientist has spoken of his "frustration" since offering university laboratories to help test for coronavirus in Wales about three weeks ago.
Prof Andrew Godkin from Cardiff University said they have been "treading water" while awaiting a decision to boost testing levels.
The Welsh Government said it planned to use universities to tackle the virus.
But Plaid Cymru said it needed to move quicker.
Cardiff University has one of the leading immunology and infection research centres in the UK.
Prof Godkin, who leads the School of Medicine, said Wales has significant laboratory capacity to help ramp up the numbers of Covid-19 tests.
"It's been deeply frustrating. We flagged up what was available about three weeks ago," he said.
"We certainly have the capacity here and in Cardiff University to really offer... a considerable number of tests."
Plaid Cymru leader Adam Price said: "The key thing now is for us to build that network of laboratories in universities, some of them in our individual hospitals across Wales, and also the indigenous private sector firms that we have in our life science industry.
"We have the capacity, we have the expertise now, but we need to move more quickly."
But other experts have said that there have been complications, and that health officials have been moving in the right direction.
Prof Ian Humphreys, the head of infection at Cardiff University, said: "We've got massive potential to help expand testing in Wales.
"We have hundreds of willing, highly-skilled volunteers really itching to help in this really difficult situation.
"There are other bottlenecks in the process of testing that we've been working for a few weeks now with Public Health Wales to identify, so things like equipment required in different stages of the testing process and also lab reagents, so chemicals, liquids, things like that, that you also need to do the test.
"So we've been working for several weeks with Public Health Wales identifying what these are by working with a team of chemists, engineers and biomedical scientists to identify how we can help iron out those bottlenecks to really ramp up capacity in Wales for testing."
In a Welsh Government briefing, First Minister Mark Drakeford said that universities had come forward.
"It is part of our plan and we will continue to work with them to make sure that we maximise whatever contribution they are able to make towards that testing effort," he said.
"We are, I think, in the final stages of identifying the capacity that they have, the staffing they have. It all has to be adapted.
"I have been very heartened by the way in which universities have come forward offering their facilities to be part of this national effort."