The number of cases of the Omicron COVID-19 variant in the UK have risen to 336 after a further 90 new cases were identified.

The figures released on Monday by the UK Health Security Agency (UKHSA) are a marginal increase from the 86 cases reported on Sunday.

According to the UKHSA, 64 of the cases were in England, 23 in Scotland and three others were in Wales.

Northern Ireland is yet to report any Omicron cases so far.

While the UKHSA has confirmed the 336 cases, experts fear there are potentially more than 1,000 cases in the UK.

They have also expressed their concern that Omicron is spreading quicker than the Delta variant, which has been the most dominant in the UK over the past few months.

The Omicron variant has been identified as having 30 different mutations, twice as many as the Delta variant.

The B.1.1.529 variant, which is suspected to be responsible for an increased number of coronavirus infections in some countries, was first reported to the World Health Organization by South Africa on November 24.

The World Health Organization (WHO) designated it a "variant of concern" due to its high number of mutations on November 26.

The emergence of the variant prompted the UK to impose restrictions on people entering the country from 10 countries in southern Africa.

(With input from agencies)