The government's website has been updated to limit the number of free lateral flow tests people can order.
Members of the public can now order a box of tests every 72 hours.
On Sunday, the website allowed people to order a box of tests every 24 hours.
The site still tells users that "you can order one pack per day." However after clicking through to the next page, the message reveals that the interval has been changed to every three days,
The update comes ahead of Boris Johnson's announcement on his plans to scrap all remaining domestic COVID restrictions in England.
The PM is expected to announce the end of the legal obligation to isolate after a positive test.
There have been reports the plan could also include the ending of free coronavirus tests for the majority of people.
Johnson will update MPs in the Commons on the plans on Monday afternoon before holding a press conference in the evening.
Watch: What is a Rapid Lateral Flow Test?
A Cabinet meeting where the plan to lift remaining coronavirus laws was set to be agreed was delayed, taking place in the afternoon instead of the morning.
Reports have emerged the delay is down to tensions between Chancellor Rishi Sunak and health secretary Sajid Javid, who are at odds over testing provisions.
A No 10 spokesman said the Commons statement will take place at around 4.30pm – slightly later than originally expected.
Johnson will then hold a press conference alongside the chief medical officer for England, Professor Sir Chris Whitty, and chief scientific adviser Sir Patrick Vallance.
On Sunday, Johnson told the BBC’s Sunday Morning programme the UK spent £2 billion on testing in January alone, and that such high expenditure did not need to continue.
The PM said the latest data meant it was time for the country to shift the balance away from “state mandation” and towards “personal responsibility”.
A number of experts have raised concerns about the impact of scrapping all restrictions.
Professor Robert West, a health psychologist from University College London and a member of the Scientific Pandemic Insights group on Behaviours (Spi-B), told Times Radio the government has moved to “abdicate its own responsibility for looking after its population”.
Speaking in a personal capacity, he said: “It looks as though what the government has said is that it accepts that the country is going to have to live with somewhere between 20,000 and 80,000 COVID deaths a year and isn’t really going to do anything about it.
“Now that seems to me to be irresponsible.”