Queen Elizabeth II has cancelled her planned virtual engagements for Tuesday due to "mild" coronavirus symptoms, Buckingham Palace said.

"As Her Majesty is still experiencing mild cold-like symptoms she has decided not to undertake her planned virtual engagements today, but will continue with light duties," said a palace spokesman.

The 95-year-old head of state tested positive for the virus on Sunday, sparking renewed concerns about her health after she spent a night in hospital in October last year.

She was forced to rest on medical grounds and cancelled a series of planned engagements, including hosting world leaders at the UN climate change summit in November.

Her appearances since then have been rare, although she returned to public duties before the start of her record-breaking 70th year as monarch on February 6.

The queen is scheduled to hold more virtual meetings later in the week, including her weekly private audience with Prime Minister Boris Johnson.

But it was reported that she will decide on whether to attend them nearer the time.

News of her illness came the day before Johnson announced all pandemic legal curbs in England would end later this week.

On Monday he said compulsory self-isolation for positive cases would stop on Thursday, urging a shift from government intervention to personal responsibility.

The move prompted concern from scientists and accusations from opposition critics that Johnson was more concerned with appeasing members of his own party angered at the curbs than protecting public health.

The monarch -- who is believed to be triple-vaccinated -- resumed in-person audiences at her Windsor Castle home west of London last week.

But she complained to one attendee of suffering from stiffness and was photographed holding a walking stick.

Her eldest son and heir Prince Charles, 73, had to pull out of a planned engagement on February 10 after testing positive for coronavirus for a second time.

Queen Elizabeth II, 95, tested positive for coronavirus on Sunday
Queen Elizabeth II, 95, tested positive for coronavirus on Sunday POOL via AFP / Joe Giddens

It was later revealed he had met his mother two days earlier.

The queen and her husband, Prince Philip, moved to Windsor in March 2020 when the pandemic first struck, given the risks of catching coronavirus due to their advanced age.

But she still made public appearances, popping up on video conference calls with members of the public, and made a rare televised address to the nation during lockdown, urging people not to give up hope.

Philip, her husband of 73 years, died in April 2021, just a few weeks before his 100th birthday. His funeral took place under restrictions limiting mourners to just 30.

Buckingham Palace announced her positive test at the weekend with a virtually identical statement to that on Tuesday.

With the infection coming two months before the queen turns 96, royal expert Richard Fitzwilliams said: "There will be concerns because of her age, no doubt about that.

"But the queen by nature is stoic. I think she's someone who looks at things in a very, very positive way," he told AFP, anticipating "reasonably regular updates" from the palace.

Elizabeth has generally enjoyed robust health over her long life, but fears grew in October after the palace was forced to reveal she spent an unscheduled night in a private London hospital.

She had been at the clinic for unspecified tests.

The Covid scare comes with the royal family mired in difficulties, including tensions with Charles's second son Prince Harry, who now lives in California with his wife Meghan.

The queen's second son Prince Andrew settled a sexual assault civil lawsuit in the United States last week, reportedly for ?12 million ($16.3 million, 14.3 million euros) -- which reports say the monarch will partly fund.

Meanwhile police in London are investigating claims that a Saudi tycoon was offered UK honours in return for donations to Charles's charitable foundation.