The NHS Test and Trace system is under fire for an online booking flaw which directs people to test centres more than 100 miles away.
Some people with coronavirus symptoms who try to book a test are told to travel to centres which would take them more than three hours to reach by car, PA reports.
Weston-super-Mare residents with symptoms are being directed to a testing centre in Cardiff, more than an hour's drive away.
This is despite there being a drive-through testing site at Bristol Airport around 25 minutes away from Weston.
A person from Ilfracombe in Devon is directed to a test centre in Swansea when they try to book a test online.
This would see them drive past centres in Taunton, Bristol and Cardiff on their six-and-a-half hour round trip, driving 175 miles in each direction.
Test and Trace is being overseen by Weston MP John Penrose's wife Dido Harding.
The cause of the problem is believed to be the system measuring journeys as the crow flies, without taking transport arrangements into account.
People in Felixstowe, Suffolk, have been directed to Clacton-on-Sea in Essex, with the website saying it is just 13.8 miles away.
But the journey is 40 miles by car, taking almost an hour to get from one place to another.
And people in the region with symptoms of Covid-19 would be forced to drive past their closest test centre in Ipswich on their way to Clacton.
Labour said problems with the booking system should be resolved as a "matter of urgency".
The party said the issues are "hugely disappointing" and called on the Government to address them as a "matter of urgency".
Shadow health minister Justin Madders said: "From the first days when testing centres were being rolled out, we have heard stories of people being sent unfeasibly long distances just to get a test, but for this to be still happening at this stage is hugely disappointing.
"Quick and easy access to testing are cornerstones of an effective test and trace system but once again the Tories seem unable to get the basics right.
"They must solve these problems as a matter of urgency."
A Department of Health and Social Care spokesperson said: “NHS Test and Trace is working, it’s completely free and is stopping the spread of coronavirus.
“Regional testing slots are allocated based on the nearest testing site with availability and we are working to ensure this takes into account journey times. Anyone with symptoms across the UK should get a test as soon as possible.”
