People in England are scrambling for free Covid tests as packs are scaled back, before most are scrapped altogether on April 1.
Those trying to order lateral flow tests are discouraged when they try to access them online.
“Most tests are now needed for people at higher risk," the online ordering system warns, adding in England, most people without Covid symptoms no longer need to take rapid lateral flow tests.
“Some people still need tests to stay safe, like: NHS staff; people who are at higher risk; people who are visiting high-risk places", the website adds.
“We want to make sure tests are available for people who need them most".
But there has been confusion within the NHS as to whether tests will still be free for staff.
The NHS Confederation said that workers may be forced to fork out about £50 a month for tests if they have to pay themselves, as it called for clarity over the issue.
The Department of Health and Social Care said that more details would be set out “shortly”.
Free universal testing for the virus will come to an end on April 1, with free tests only being made available to the most vulnerable.
Officials have previously said that the number of free tests available each day will be capped to “manage demand” as the government scales back free testing for people in England.
The public have been encouraged not to stockpile test packs but since ministers announced the end of the free testing programme for most of the population, it has been difficult for many to access them.
But the UK Health Security Agency (UKHSA) said that availability is refreshed regularly.
A UKHSA spokesperson said: “As set out in the Living With Covid plan, from April 1 free tests will only be available for certain groups who are at most risk from the virus.
“In preparation for this change, the gov.uk home ordering channel is asking users to only order test kits if you’re eligible for new Covid-19 treatments, work or volunteer in a high-risk setting or support people who are at higher risk from Covid-19.
“Tests should only be ordered after you have used up any kits you already have at home".
Scotland will also see free testing end for most people from the end of April, while in Wales free mass testing will be phased out between the end of March and June to be replaced by targeted testing.
It's unclear what will happen in Northern Ireland, given there is currently no functioning executive.