A teachers' union has called for all schools in Northern Ireland to stay shut until February at the earliest.
he NASUWT has said they agree with their counterparts in England that schools are "unsafe" and should stay closed, at least until the current lockdown ends.
Union official Justin McCamphill said he was "very disappointed" with First Minister Arlene Foster's proposal that remote learning should only be for a short period.
Mr McCamphill told the Belfast Telegraph that "blended learning", as he described it, "needs to continue for as long as is necessary".
"We are calling on the Executive to review their position in relation to primary schools and to extend blended learning for them, at least until the end of January," he said.
"Our schools are not safe. With the massively increased number of Covid infections it's inevitable that coronavirus is going to spread within schools when they reopen therefore it's important that caution is applied."
He added: "The First Minister, the Education Minister and the Executive need to be guided by the science on this.
"We are calling for blended learning for all school children except for the vulnerable and the children of key workers, to continue for the foreseeable future."
Mrs Foster said remote learning for school children should only be for a short period.
Speaking on the Andrew Marr show on the BBC, she also expressed concern about the life chances of young people during the pandemic. Primary pupils are to be taught remotely for the week from Monday until Friday, January 8 as the spread of coronavirus surges.
But Mr McCamphill said all schools need to be closed until February to coincide with the current lockdown.
"There are two aspects to closing schools," he said. "There's the transmission that occurs in schools but then there's the associated transmission, such as children travelling on buses and parents dropping children off.
"If we want the lockdown to be effective, and if we want to get Covid under control, we must take all the necessary steps otherwise our health system won't be able to cope."
Mr McCamphill said he was disappointed after Mrs Foster told the BBC that keeping children in school was a priority.
The DUP leader said: "We will do all that we can to keep pupils in school. We do recognise that with this new mutant version of Covid-19 there are difficulties and it transmits among younger people, and we have to take that into consideration."
However, Mr McCamphill said the DUP “need to start listening to the scientific advice and acting on it”.
His comments come after all four teaching unions in England said it was "unsafe" for schools to reopen and called for their closure for the next two weeks.
But Boris Johnson said parents should send primary-age children back to schools that are open this week. The Prime Minister also said he has "no doubt" that classrooms are safe and that the risk to young people was "very, very small".
Mr Johnson told the Marr Show: "Schools are safe. It is very, very important to stress that.
"I would advise all parents thinking about want to do, look at where your area is, overwhelmingly you'll be in a part of the country where primary schools tomorrow will be open."
Meanwhile, Northern Ireland nursery schools leaders have urged Mr Weir to treat them the same as their primary and secondary school counterparts.
In a letter, the North and South Belfast Nursery Schools Principals Group urged him "to hear the voices from the sector working on the ground in these unprecedented times".
They added: "We urge you to apply the same safety measures around delayed opening for primary school to all nurseries and preschools, thus enabling them to offer the same essential care for key workers and vulnerable children, to minimise contact and the spread of the virus."