Support for Fianna Fáil has fallen by four points to 20%, the latest Sunday Times/Behaviour & Attitudes opinion poll has suggested.
Sinn Féin support is up one point to stand at 32% in the poll carried out between 4 and 14 March.
Fine Gael on 23% and the Green Party on 5% are both unchanged.
Labour also remains on 5% support, while the Social Democrats are up two points to 4%.
Independents are unchanged on 9% and Solidarity/PBP are up one point to 2%.
This opinion poll has a margin of error of 3.3%.
