Britain has reported more than 100,000 new daily COVID-19 cases for the first time since widespread testing was introduced.

There were 106,122 cases reported on Wednesday (local time), compared with 90,629 on Tuesday.

The rapid spread of the Omicron variant has driven a surge in cases in the past seven days, with the total rising by 643,219, or 59 per cent, according to government data.

Many industries are struggling with staff shortages as sick workers self-isolate, and hospitals have warned of the risk of an impact on patient safety.

On Wednesday, the British government said it was reducing the COVID-19 self-isolation period to seven days from 10 for people in England who had a negative result on a lateral flow test two days in a row.

On Tuesday, Prime Minister Boris Johnson ruled out new restrictions before Christmas, saying there was uncertainty about the severity of Omicron and hospitalisation rates.

However, he did not rule out further measures after the holiday if the situation deteriorated.

There were 195 patients hospitalised with Omicron up to Tuesday and 18 deaths of people with the variant, according to separate data.

The total number of COVID-19 patients in hospital was 8008. That is slightly up in the past week but still far below the levels of more than 38,000 last January.

There were 140 deaths within 28 days of a positive case, down from 172 the previous day.