Liz Canavan, of the Department of the Taoiseach, said that businesses which open against the country’s current restrictions are “penalising” small enterprises.
As part of Level 5 restrictions brought into effect on Thursday, only shops selling essential items are allowed to open.
Under Government guidelines, retailers that have “discrete spaces” for essential and non-essential items have been told to separate the relevant areas.
However, it has emerged that some retail businesses have been using loopholes in the legislation to remain open.
Ms Canavan urged all shops to comply with the regulations.
“Those businesses that flout the regulations, either by opening or by selling non-essential items, are further penalising other small and local enterprises,” she warned.
“That not only is just not fair play, it’s contrary to the law. Where the premises is an essential retail outlet, it can only provide access to that part of the premises it is operating as an essential retail outlet.”
Ms Canavan also said there has been a lot of speculation in recent weeks about who might be to blame for the soar in Covid-19 cases across the country.
“The biggest risk in all the debate is that we forgot that no measure the government can take will be more important or more effective than what you can do,” she added.
“We are all familiar with people who want to adapt the restrictions, look for the loopholes, or try to rationalise the activity they want to do is the same as the one that is permitted.
“There is a focus on what you can’t do, rather than what you can do.
“This is all very normal behaviour but that debate is maddening for those who are complying. It understates the number of people who are doing their level best and it’s really not that helpful.
“It’s all very frustrating for the staff and businesses who want to be open, who are worried about their finances and the future of their businesses, but are doing what they have been asked to do.
“The best way the public can support those people is by following the public health advice and breaking the path of the virus.”
She also urged the public to support and buy from local businesses.
In the Covid-19 government briefing, Ms Canavan also acknowledged the reduction in transport capacity in recent days, adding that the Department of Transport is working to resolve issues.
Under Level 5 restrictions, public transport is operating at 25 per cent capacity.
Public transport is being provided for essential workers and students attending school.
“The Department of Transport is engaging with the National Transport Authority and the NTA is working to identify particular pressure points with a view to address them where possible,” she added.
“If you do need to use public transport, remember it is for essential purposes.”