He will be accompanied by England’s Chief Medical Officer Professor Chris Whitty at the 5.30pm event.
The briefing was originally meant to take place at 5pm, but Number 10 has announced it has been has been delayed.
Ministers are considering a range of actions in response to the spread of the Indian coronavirus variant of concern as new figures show cases have more than doubled in a week.
Data from Public Health England shows an increase in cases from 520 to 1,313 this week in the UK.
In London, the number of cases has risen to 400.
Ministers are facing growing questions over why they did not put India on the “red” list of countries sooner to restrict travel from there to the UK to prevent the importation of new variants.
The re-opening of indoor service in pubs, restaurants and other parts of the hospitality sector in Britain is still going ahead on Monday as planned, according to vaccines minister Nadhim Zahawi.
However, he did not rule out a delay to the final stage of easing the lockdown on June 21, or on lifting the work-from-home guidance.
He also appealed to the public to help to suppress the Covid-19 infection rate in the face of the Indian variant if the planned lifting of restrictions in June is to stay on track.
Mr Zahawi urged people in the 15 areas of England with spread of the Indian variant of concern to follow local health advice, get tested and isolate if they test positive.
Asked if the June 21 road map easing - when all legal limits on social contact are due to be lifted - could be put on ice, Mr Zahawi told LBC’s Nick Ferrari that this Monday’s reopening of indoor meet-ups “is still on”.
When pressed on whether the plans for June 21 could be paused, he said: “The way we don’t have to do that is by everybody doing their bit, by taking the two tests a week, doing your PCR test in those areas, and to isolate, isolate, isolate.
“We have got to break the cycle of infection, because one of those big tests was infection rates have to be suppressed, and the other big test is variants.
“If those cause a problem, then the tests will fail. The four tests have to be met for June 21.”
Mr Zahawi said the seven-day rolling average figures for infection show a 12.4 per cent rise, but hospital admissions are down by 7.9 per cent.
“That is good news because it tells you that the vaccines are clearly working in terms of hospitalisation and severe infections... but the infection rate is what is concerning, which is why we have to surge test and then isolate,” he said.
The Government is looking at ways to “flex” the rollout of vaccines in the worst hit areas such as the North West, including vaccinating everyone in multi-generational households from 18-year-olds to grandparents, Mr Zahawi said.
More vaccine doses have been sent to Bolton, which has a particularly high rate of the Indian variant, while 800,000 PCR tests have been sent to 15 separate areas of the England, including parts of London and Merseyside.
One option also being considered by clinical advisers to the Government, who are meeting on Friday, is to bring forward the date for second doses of vaccine for the elderly and vulnerable in regions where the Indian variant is spreading.
Asked on BBC Breakfast what is stopping vaccines being given to younger age groups in affected areas now, Mr Zahawi said it takes three weeks to build protection from a first dose and to have any effect on transmission of the virus.
The Government is expected to make further decisions regarding the vaccine programme once clinical advisers have looked at the evidence and made recommendations.
Bedford Borough Council is among those calling for vaccines to be made available for over-16s in the face of the variant.
Greater Manchester Mayor Andy Burnham also told BBC Breakfast: “We do say to the Government they do need to go further now and allow those extra vaccine supplies to be used in vaccinating the younger working age population, the student population.
“That is what is needed if we are to make the most decisive and effective intervention into this situation that we can right now.
“We recognise the pressure on vaccine supplies all over the country but we have been moving at a pace where we have been treating all areas equally, and I think the time has now come to recognise areas with the highest case rate do need to be able to move more quickly down the ages.”
He said there are “younger people in places like Bolton who are in quite insecure work, so if they become ill they fear they won’t be paid if they have to take time off work” for self-isolation.
He said he does not support local lockdowns which “really didn’t work” last year, adding: “We are in a different situation this year because, even though we are seeing spread of the Indian variant in Bolton, we are not seeing the same numbers of people going into hospital because obviously older people are more protected now.
“So we don’t need to have the same response that we had last year.
We do believe if we move quickly on vaccination we can take away any risk of a local lockdown.”
There is no current evidence that vaccines do not work against the Indian variant, which is thought to be at least as transmissible as the Kent variant of the virus.
Paul Hunter, professor in medicine at the University of East Anglia, said the planned June 21 lockdown lifting could be in doubt if the Indian variant causes increases in cases in elderly people and a rise in people needing hospital care.
He told BBC Radio 4’s Today programme: “I think the big question is how many of people who are getting the Indian variant will end up requiring hospitalisation?
“And at the moment the hospitalisation rate doesn’t seem to be increasing yet, although if this becomes much more common we’ll almost certainly see some increase, so I think it’s certainly a concern.
“I think the step four is in doubt in June now, but we really need to see what impact it has on severe disease before we can really be certain.”
Asked why June 21 is in doubt, he said: “Well, because if the epidemic continues to increase, if the Indian variant of the epidemic continues to increase at the same rate as it has over recent weeks, we’re going to have a huge number of cases by June.
“The issue though is that because it seems to be spreading in unvaccinated younger people at the moment and not yet that much more active in older people, maybe we’ll be able to weather it and we’ll still be able to have the step four in June.
“But if that increases cases in elderly and starts to increase hospitalisations, and puts pressure on the NHS again then I think step four would be in doubt.”
Prof Hunter said the Indian variant “clearly has been out-competing” the Kent variant in a number of areas around the UK.