The party led by Gerry Adams polled 26 percent, just a point above Fine Gael led by Taoiseach Enda Kenny.
Sinn Fein was five points up on the previous Millward/Brown opinion poll for the paper while Fine Gael was three points up.
The two parties have moved decisively ahead in the race to lead the next government after the next general election which almost certain to be in spring 2016.
Fianna Fail moved one point up to 19 percent while Labor – the minority partner in the present government – was also up a point to six percent.
Biggest losers were the independents which polled 32 percent last year but were down this week to 23 percent.
The poll also found support for the formation of a new political party continues to fall.
The leaders of all the main political parties recorded increases in their personal satisfaction ratings. Kenny’s support is up three points to 24 percent, Tanaiste (Deputy Prime Minister and Labor Party leader) Joan Burton is up one point to 23, Fianna Fail leader Micheal Martin is up five points to 29, and Sinn Fein Adams is also at 29, an increase of six points.
The poll also showed that 18 percent would like to see Health Minister Leo Varadkar lead Fine Gael into the next election while only 11 percent want to see Kenny do so.
When asked if Varadkar’s decision to come out as gay made them more or less likely to want to see him as Taoiseach, 72 per cent said it “makes no difference.”
Varadkar played down the support for him to be the next taoiseach.
“I’m not running for taoiseach. I’m contesting the general election in Dublin West in about a year’s time and it’s not a Fine Gael stronghold and it’ll be a battle to hold onto that seat. That’s my only personal priority in term of politics at the moment,” he said.