A leading local doctor has voiced deep scepticism about the value of face masks in reducing the spread of coronavirus.
Dr Anne McCloskey, a GP based in Londonderry, likened it to "using a sheep fence to keep out mosquitoes".
She said it was "ridiculous" to contemplate making them compulsory.
It came as a row broke out over a Government decision to make coverings mandatory in shops in England.
Those who fail to comply with the new rules will face a fine of up to £100, enforced by police.
Health Secretary Matt Hancock said coverings would help give people "more confidence to shop safely" and help protect staff.
The Executive Office said the issue was kept "under continuous review". Infrastructure Minister Nichola Mallon said she supports the use of face coverings in shops here.
Chief Medical Officer Dr Michael McBride said wearing masks was the "right thing to do, the responsible thing to do".
However, other retail and medical figures said it was not necessary for them to be compulsory.
Dr McCloskey, deputy leader of Aontu, who came out of retirement at the start of the pandemic, said official advice on the matter was inconsistent.
"The evidence on this changes; the World Health Organization has changed its mind on face coverings a couple of times, but to me the striking thing is the timing," she said.
"We are four months into a pandemic which is now over - the peak deaths was in early April - and they are talking about introducing face masks at this stage. It is ridiculous and is not going to be effective in a healthy environment.
I have concerns about people who suffer from COPD, asthma or anxiety. Face coverings will put them at risk of making their conditions worseDr Anne McCloskey
"The incidence of this virus is way down. There are cases but they are people with the virus. They are not dying from it, which is what happens with viruses, they get less dangerous over time.
"People do become infected with it, but that is what the NHS is for, that is what we do.
"The other thing that concerns me is around the face coverings themselves, which won't be standardised as far as I know, so it will be like using a sheep fence to keep out mosquitoes,
"I have concerns about people who suffer from COPD, asthma or anxiety. Face coverings will put them at risk of making their conditions worse."
Aodhan Connelly, director of the Northern Ireland Retail Consortium, said the situation here was different to England because of a lower infection rate.
He told the BBC: "It needs to be realised that retailers and our staff aren't there to do the enforcement of it, and also we are going to need time to bring it in."
Public health expert Gabriel Scally told the BBC: "The incidence of the new cases is completely different in Northern Ireland and England, so there is a question about whether they are needed, and they won't be if we can keep the number of cases way, way down.
"I absolutely agree with them on public transport, and the evidence is increasing about the value of face coverings, but they are really at maximum value when everyone is using them."
Dr Tom Black, Northern Ireland chair of the British Medical Association, supports greater use of face coverings.
He said: "In my own work and social environment I would recommend face coverings and I think most people will get into the habit of wearing them."
He believes most people will move to using face masks "over the next few weeks".
In England a row is brewing over how the rules would be enforced. Police chiefs said officers should only be involved "as a last resort" if shoppers refuse to wear face coverings.
Senior officers were said to be blindsided by the announcement, with the National Police Chiefs' Council saying shopkeepers should be expected to manage entry into their stores and compliance with the law.
Angry Conservative Party members cut up their membership cards in protest at the move. The hashtag #NoMasks and the word "muzzles" were both trending on Twitter.