Britain will deploy troops to hospitals in London to alleviate severe staff shortages caused by the Omicron outbreak, the Ministry of Defence (MoD) said Friday.

Around 200 armed forces personnel will join health workers in the capital, which has been particularly badly hit by the recent upsurge in coronavirus cases leading to mass staff absences in hospitals.

"The men and women of our armed forces are once again stepping up to support their dedicated colleagues in the NHS (National Health Service) as they work hand-in-hand to protect the nation from Covid-19," said Defence Secretary Ben Wallace.

"They have shown their worth time and again throughout this pandemic, whether driving ambulances, administering vaccines or supporting patients in hospital, and they should be proud of their contribution to this truly national effort."

The deployment will include 40 military medics and 160 general duty personnel, said the ministry.

Britain on Tuesday recorded 218,724 daily cases of the virus, the highest figure since the pandemic started.

Although deaths and patients requiring ventilators have remained steady, the sheer number of health staff testing positive for the virus and having to self-isolate is putting pressure on the system.

A sign warns commuters in Canary Wharf, east London that more than 80% of people in intensive care with COVID-19 are not fully vaccinated. Photo: AFP

Matthew Taylor, chief executive of the NHS Confederation, said there were several thousand NHS staff absent and that "having 200 extra people is going to help but it's only a very small part of what will continue to be a very difficult situation".

Prime Minister Boris Johnson on Tuesday said hospitals were on a "war footing" due to staff shortages, with many hospital groups declaring "critical incidents" because of the threat to crucial services.