Appointments at a pilot coronavirus test centre in Stoke-on-Trent were booked up within half an hour of opening online, a council says.
Fenton Manor sports complex offered 100 tests on both Monday and Tuesday after a pilot to "tackle a shortage" in national testing capacity was extended.
"Very high demand" meant some could not get tests at the regional centre, the Bet365 stadium, the city council said.
Tests will also be held at two other community venues.
One hundred daily tests are offered at the Red Lion and St Chad's community centres in Burton upon Trent on Wednesday and Thursday respectively, before testing moves to the Kingston Centre in Stafford on Friday.
The tests, which are for residents from the area who have symptoms, must be booked 48 hours in advance.
A total of 500 available tests were fully booked last week when the pilot began, but 70 people did not turn up, said Staffordshire County Council, urging people to cancel tests no longer needed.
Both councils also asked people to try booking on the national system first and only when they really needed a test.
In Stoke-on-Trent, five of the 195 people tested were found to be positive for Covid-19.
Council leader Abi Brown said due to testing on Monday alone it meant 86 people were "able to go back to work or school".
Rising demand is among the reasons the national system has struggled to cope.
Staffordshire Council leader Alan White said he hoped the pilot scheme could be extended beyond this week.