The speed at which coronavirus home tests have been processed in Wales has fallen dramatically.
In the final week of August, 8% of home tests were processed within a day and only 24% were processed within two days.
At the end of July, 50% of home tests were processed within a day and 88% within two.
Welsh Government statisticians said the fall was due to demand exceeding Lighthouse laboratory capacity.
The delays have also meant that less than half of home tests had been processed within three days - this figure was 99% in July.
Lighthouse labs are a UK-wide network of specialist coronavirus laboratories and most Welsh tests are processed in them.
On Tuesday, the UK government apologised for the delays at Lighthouse labs and a backlog at the labs has led to a drop in available testing slots.
Capacity problems at the labs have also resulted in people being asked to travel long distances to access drive-through tests.
Coronavirus cases have been rising in parts of Wales over the past few days, with 165 new cases reported by Public Health Wales on Wednesday.
The spike has seen Caerphilly county placed in Wales' first local lockdown after 151 cases in the past seven days.
Meanwhile, 100 cases have been reported in Rhondda Cynon Taff, prompting the council to open a temporary testing centre at Oldway House in Porth from 09:30 BST on Thursday for one week.
⚠️Further info following yesterday's announcement of temporary testing centre opening in Porth on Thursday 10 September. Tests are ONLY to be booked if you CURRENTLY HAVE coronavirus symptoms⚠️— RCT Council (@RCTCouncil) September 9, 2020
Test bookings NEED to be made IN ADVANCE via this link - https://t.co/R9CkjIEhGT pic.twitter.com/z2uqtVzxY7
In a statement on Tuesday, the Welsh Government said: "We have raised this issue with the UK government, which runs the Lighthouse lab testing system and we expect these issues to be resolved quickly to ensure people in Wales who have suspected coronavirus symptoms can receive a test as close to home as possible.
"We have recently announced £32m to increase capacity to process tests at laboratories in Wales, which includes extending our regional labs to 24-hour operation and six new 'hot labs' at hospitals across Wales.
"This investment will increase our testing resilience ahead of the winter."