Three of the country's four main parties have experienced a drop in support.

The Sunday Independent Millward Brown survey was carried out for nine days until Friday and shows Fine Gael is down 3 points to 27 per cent.

Coalition partners Labour don't fare any better - down 4 points to 8 per cent and Fianna Fáil drops 5 points to 21.

That puts them behind Sinn Féin who go up 6 to 22 - their highest level of support since the General Election.

Fionnan Sheahan is the Group Political Editor for the Sunday Independent, he explains the reason behind the changes: