Fine Gael has seen its support fall to 20 per cent, the lowest level in a year, in the latest political opinion poll while their coalition partners Fianna Fáil are up three points to 19 per cent.
Sinn Féin remains the most popular party in the country, sitting with 31 per cent. Fine Gael's fall to 20 per cent marks a two per cent decrease on last month.
The Sunday Independent/Ireland Thinks opinion poll showed Sinn Féin far ahead once again.
The Social Democrats have fallen to 5 per cent, down from 9 per cent last month.
Their increase had been put down to new leader Holly Cairns, a Cork South-West TD.
However, she remains the most popular party leader in the country with an approval rating of 44 per cent. Tánaiste Micheál Martin is second on 43 per cent, while Sinn Féin leader Mary Lou McDonald has seen her popularity fall to 39 per cent, down four points.
Forty-two per cent of the electorate would prefer a Sinn Féin-led government while 40 per cent support the existing Coalition.
The smaller parties did not fare well in the latest poll.
The Green Party is down one point to 3 per cent, Labour is up one point to 4 per cent, while Solidarity People Before Profit is also on 4 per cent.
Aontú is down one point to 2 per cent. Support for Independents is up by three points to 13 per cent.