The new infections join the previous 29 confirmed cases of the of the variant known by scientists as B.1.1.529, bringing the total number in England to 104.
The UK total has now reached 150.
People infected with the omicron variant in England have now been located in the East Midlands, East of England, London, North East, North West, South East, South West and West Midlands.
The UK Health Security Agency (UKHSA) said targeted testing was being carried in locations where the positive cases were likely to be infectious.
The first omicron coronavirus case was also confirmed on Friday in Wales.
The case was in the Cardiff and Vale University Health Board area and is linked to international travel, the Welsh government have said. Public Health Wales have since said there is no evidence of wider community transmission.
Meanwhile, a further 16 cases were identified in Scotland on Friday - bringing the country’s total to 29.
As it stands, there remain no confirmed omicron cases in Northern Ireland.
Dr Jenny Harries, chief executive of UKHSA, has said a number of the cases detected have no links to travel, suggesting that the UK has “a small amount of community transmission”.
She said: “Increased case detection through focused contact tracing has led to more cases of the omicron variant being identified and confirmed, as we have seen in other countries globally.
“We are continuing to monitor the data closely. Teams nationally and locally are working at pace to identify and trace all close contacts of every Omicron case. It is critical that anyone with Covid-19 symptoms isolates and gets a PCR test immediately.
“We have started to see cases where there are no links to travel, suggesting that we have a small amount of community transmission. That’s why it’s so important that everybody, everywhere, takes simple steps to protect themselves from infection. Please wear face coverings in line with government guidance, let in fresh air when mixing indoors and wash your hands regularly.”
She added: “Vaccination is critical to help us bolster our defences against this new variant so please get your first, second, third or booster jab as soon as you are eligible to protect yourself, your families and your communities.”
In light of the discovery of the new omicron cases in the UK, the government have also urged people to remain vigilant in taking a PCR test should they be contacted or have coronavirus symptoms.
They have also said that they are currently working to gather and disseminate scientific information to the public “in order to inform the right balance of interventions to prevent transmission and protect lives.”
But Boris Johnson said Christmas should go ahead "as normally as possible" this year despite concerns about the omicron variant.
Speaking during a by-election campaign visit to Oswestry in North Shropshire, the PM said that people did not need to cancel parties or nativity plays.
Asked what he had to say to bereaved families following claims No 10 had held parties last year in breach of restrictions at the time, Mr Johnson said: "What I've said throughout, since this thing was brought up, was that's not true, we've followed the guidance throughout and continued to follow the guidance.
"And on the subject of Christmas parties, I've noticed there's been quite a lot of to-ing and fro-ing about it, people concerned that they need to cancel their Christmas parties. That's not right, we're not saying that and we're not saying that nativity plays have to be cancelled.
"I believe very strongly that kids should be in school and I also think that Christmas should go ahead as normally as possible. But the key point, the key point is that whatever the risk omicron may pose, or may not pose, the booster is everywhere and always, vaccination is going to be your best protection, so everybody should get it."
Asked again repeatedly if he did have a party or gathering, the prime minister repeated the phrase: "We followed the guidance."