Stormont leaders have been accused of “dithering and delay” over action to stem the spread of a new strain of coronavirus.
Powersharing partners the DUP and Sinn Féin are split on what to do.
Covid-19 is out of control in some places after a mutation was discovered in London and Kent, England's health secretary has said.
Northern Ireland is considering strengthening its travel locator paperwork and is consulting legal experts.
Sinn Féin’s Pat Sheehan alleged the devolved administration was engaged in “dithering and delay”.
He urged ministers to act quickly on travel, adding: “It is not a sustainable position going forward.”
His party colleague, John O’Dowd, said: “Sometimes there are times to act and seek forgiveness later.
“Surely it is time to act.”
Stormont Health Minister Robin Swann said he was part of a five-party coalition which needed to achieve consensus.
Executive ministers have debated amending the 1967 Public Health Act to introduce short-term travel restrictions.
Sinn Féin supported the move, however practical issues were raised around how quickly such a ban could be introduced, given the time it would likely take for the Department of Health to draw up regulations to bring it into effect.
The DUP position was that UK internal travel is already banned from Tier 4 areas in England, so there is no need for added Stormont legislation to enforce that.
Mr Swann said: “This is an exceptionally sensitive time.”
Hospitals are admitting 400-500 Covid-19 patients every day in Northern Ireland, the minister said.
Ambulances were queued outside a hospital last week. One emergency patient in Belfast waited 28 hours for a bed.
Mr Swann told a Stormont Assembly committee they needed to protect vital services.
“This is to take the pressure off our hospital system,” he said.
He said scenes of lorries queued near Dover in Kent highlighted the need to protect Northern Ireland’s food and medicine supplies.
In the last two weeks, 23 cases of coronavirus were reported amongst passengers travelling there from the rest of the UK, the Minister said.
He noted people living in higher tiers of restrictions in the UK are asked not to travel to other parts such as Northern Ireland.
Mr Swann said ministers were reliant on guidance coming from the UK government.
He added: “We are engaging with the Attorney General to see what can be done, what is necessary to do.
“That will be a decision for the Executive to make together.”
He said vaccination was proceeding apace as he detailed efforts to protect care home residents.
On Saturday night around 50 per cent of care homes across the North were vaccinated, just under 6,000 residents.
Debate has surrounded the reopening of schools after the Christmas break.
Education Minister Peter Weir is considering moving some post-primary pupils to remote learning for a period in January.
Mr Swann said: “I do not believe that a return to school as normal in January is a sustainable position.
“My view on this matter is informed by advice from the chief medical officer and chief scientific adviser.”
He said additional measures should be put in place.
“All options should be considered,” he said.
He added that medical advice given to the education minister included guidance from Sage, as well as clarity provided by health department officials.
