Wearing face coverings in shops will be made mandatory, Micheal Martin has confirmed.
On Monday, the wearing of face coverings on public transport was made law, punishable by a €2,500 fine or up to six months imprisonment.
Retail staff will also be required to wear masks unless there is a partition between them and the customer or a distance of two meters.
The news comes amid Government concerns over a worrying rise in new Covid-19 cases in the past week.
Taoiseach Micheal Martin made the announcement this evening after a Cabinet meeting, which discussed recommendations made by the National Public Health Emergency team.
After growing concern over the spread of the virus through house parties, the number of people allowed to visit an individual home has been reduced to 10, from no more than four different households.
The extension of phase three means that facilities such as pubs, nightclubs, casinos, theatres, cinemas and galleries will now be unable to reopen.
Pubs and restaurants that have already opened can continue to operate in line with public health advice.
