Another COVID variant has been detected which appears to be more contagious than a mutated version of the virus that forced the cancellation of Christmas in the UK.

British health secretary Matt Hancock said two cases of a new strain originally identified in South Africa had been picked up in the UK.

The variant has raised fresh concerns as the UK expanded its toughest Tier four restrictions to include more regions.

“This new variant is highly concerning because it is yet more transmissible and it appears to have mutated further than the new variant that has been discovered in the UK,” Mr Hancock said.

“Both are contacts of cases who have travelled from South Africa over the past few weeks.”

Mr Hancock announced new restrictions for travellers arriving in the UK from South Africa while contacts of people arriving from South Africa will go into quarantine.

“These measures are temporary while we investigate further this new strain which is shortly to be analysed at Porton Down,” he said.

• Related: What experts know but the new COVID variant
• Related: Countries bar British travellers over mutation fears

Much of Britain is being locked down to contain the spread of the first faster-spreading variant which was responsible for about 60 per cent of cases in London.

Australia has detected four cases of the variant – two each in NSW and Victoria, the Australian Health Protection Principal Committee (AHPPC) confirmed in a statement.

” All cases have been or are being managed in hotel quarantine and the variant has not spread into the community.

“Australia has a world class system for genetic analysis of SARS-CoV-2 to be able to detect occurrence of this variant.”

NSW Christmas restrictions

Drive-through testing at Bondi. Photo: AAP

People at the epicentre of the recent COVID-19 outbreak can now welcome five visitors to their homes as restrictions were partially relaxed for Christmas.

NSW will have a four-tiered system of restrictions between Christmas Eve and Boxing Day before returning to previous settings, Premier Gladys Berejiklian announced on Wednesday.

The approach has seen the northern beaches split in two, with the toughest conditions reserved for those north of the Narrabeen Bridge. The area is the epicentre of the recent cluster, which now totals 97 infections.

Residents can now host up to five people in their homes, as long as the visitors live in that designated zone.

Ten visitors are allowed to households in the southern part of the region, but locals must not leave the area for gatherings elsewhere. Primary school-aged children and younger are not included in the ten.

Pubs and clubs are still closed in the northern beaches, with residents only permitted to leave their homes for a limited set of reasons.

Restrictions for regional NSW remain unchanged, while up to 10 people and unlimited children aged under 12 will be permitted to visit another home over the three-day period.

Thousands of people will continue to self-isolate over Christmas after visiting a venue at the same time as a COVID-19 positive case.

NSW again recorded eight locally transmitted coronavirus cases in the 24 hours to 8pm on Tuesday, with seven connected to the Avalon cluster.

The outbreak is likely to not only change Sydneysiders’ Christmas plans, but their New Year’s Eve plans too.

The Australian Medical Association has called on the NSW government to cancel Sydney’s iconic fireworks display.

“The NSW government should consider cancelling the New Year’s Eve fireworks display to discourage crowds and avoid any confusion in its public messaging,” federal AMA president Omar Khorshid said in a statement on Wednesday.

“We must be prepared to tighten general restrictions even further if we continue to see evidence of the virus spreading in areas outside of the northern beaches.”

A decision about the New Year will be made after Christmas.

All state and territory borders are closed to people travelling from Greater Sydney.

-with AAP