There are concerns people in Wales are still not able to book drive-through coronavirus tests due to not being able to access a UK website.
In England, Scotland and Northern Ireland members of the public are able to book tests online.
Despite it being announced last week that announced Wales would join the service, it is still unavailable.
The Welsh Government said an update would be provided as “soon as possible”.
Critical workers are able to book tests by contacting testing centres directly.
But unions said the lack of testing was concerning for workers, especially those on zero-hour contracts or jobs where they were not entitled to company sick pay.
A Welsh Government spokesman said work was being done on access to the site at the moment.
“As soon as this work is finalised, daily test slot allocations will be available for critical workers,” he said.
On Monday, the Welsh Government said critical workers and members of the public would be able to use the UK booking site for drive-through appointments “soon.”
Home test kits are available to everyone across the UK, but availability depends on demand.
The decision to opt into the UK system meant ministers in Cardiff ditched plans to develop Wales’ own online-booking system.
Gemma Powell, a supermarket worker from Bridgend, wanted a coronavirus test last week when she developed a dry cough.
“I couldn’t order a home testing kit but I finally managed to get through to book an appointment at a drive through screening in Pencoed,” she said.
“The system is making it so difficult to get a test.
“The number I phoned was the Abercynon helpline which I thought was the wrong number – I phoned this for the correct number for Bridgend area but it turned out to be for my area.
“If I hadn’t tried this number I would still be without a test appointment.
“The information people need is hard to get hold of.”
The test came back negative, meaning Gemma was able to return to work after missing four days.
Wales Trades Union Congress (TUC) general secretary Shav Taj said the system is “still confusing people” and “needs greater clarity”.
She said it was a concern, in particular for workers not entitled to paid time off and company sick pay if they needed to get tested and self-isolate.
“Many key workers are low paid or on zero hours, precarious agency contracts,” she said.
“They can’t survive off statutory sick pay alone.”
Angela Burns, who speaks on health for the Welsh Conservatives, said it was “not a surprise that there is confusion and difficulties booking a test”.
“The Welsh Government spent nearly a month delaying access to an online portal, wanting a distinctive Welsh approach to the pandemic instead of using the UK Government’s online portal,” she said.