Support for both Fianna Fáil and Labour is declining while Sinn Féin is increasing in popularity, according to the latest opinion poll.

The Red C poll, in tomorrow's Sunday Business Post, indicates a narrowing in the gap between the current Government and the alternative coalition of Fine Gael and Labour.

Since the last in the series of monthly tracking polls by Red C was taken at the end of February, there have been a number of political developments.

Fine Gael published part of its taxation proposals for the General Election and both the Greens and Sinn Féin held party conferences.

Sinn Féin also enjoyed a successful election in Northern Ireland and has been central to negotiations to re-establish power-sharing institutions.

This month's poll was taken before this weekend's Fianna Fáil Ard Fhéis but the party will be disappointed to be down two points to 36% support.

Fine Gael are up one point to 23% but their partners in Labour are down two to 12%.

The Greens, who could be another colour in a Rainbow government, are unchanged at 8%. While the PDs lose one point, down to 3%.

The biggest winners are Sinn Féin, up three points to 10%, while the Independents and others are up one to 8%.