Lateral flow home test kits are unavailable on the Government website, as people wait to book a coronavirus vaccine.
The Government website on Monday said “there are no more home tests available”.
It advised people to “try again later” or to book a test site appointment instead.
It has been announced that double-jabbed people identified as a contact of someone with Covid-19 in England will be told to take a daily rapid test for seven days from Tuesday.
Unvaccinated people will need a negative home test as an alternative to gain entry.
One person said on Twitter: “Tried to order a lateral flow test kit and the NHS site says they have no more! What’s going on!”
However, there appeared to be no problems with the availability of PCR home test kits.
It comes as people trying to book a Covid-19 booster jab in England have been advised by the NHS to try later or tomorrow as people faced a queue on the website.
In a tweet, the NHS said: “The Covid vaccine booking service is currently facing extremely high demand so is operating a queuing system.
It comes on the first day that 30 to 39-year-olds in England can officially book the jab.
The service had already booked more than 140,000 vaccine appointments on Monday, NHS Digital said, with people waiting several minutes.
Long queues have also been seen outside vaccination sites, as Health Secretary Sajid Javid said the Government will “throw everything at” the Covid booster programme to tackle the Omicron variant.
The PA news agency has approached UK Health Security Agency (UKHSA) for comment.