The Sinn Féin leader isn’t in favour of closing the border with Northern Ireland in an effort to contain COVID-19.
Mary Lou McDonald was speaking as the Republic spends its first day under Level 5 restrictions, while Northern Ireland continues to have one of the highest reproduction rates in Europe.
The six counties have a reproductive rate of between 1.4 and 1.8, meaning the virus is continuing to spread rapidly.
The 14-day incidence rate in Northern Ireland per 100,000 population is more than double that of the Republic.
Mary Lou McDonald was asked if the border should close for six weeks to supress the virus.