Sinn Féin now lies in joint first place with Fianna Fáil in terms of party support as Fine Gael has slipped back, a dramatic new opinion poll reveals.

The latest Business Post/Red C poll are likely to heap pressure on Taoiseach Leo Varadkar and his Fine Gael team which has faltered since the start of the campaign and as things stand look set to lose power.

It is the first time ever that Sinn Féin has been on the highest vote share in a Red C poll. The party was only ever ahead of Fine Gael once before.

The state of the parties is as follows: Fianna Fáil 24% down 2; Sinn Fein 24% up 5; Fine Gael 21% down 2; theGreen Party 7% down 1; Labour 5% up 1; Soc Dems 3% no change; Soliddarity-PBP 1% down 1; Aontú are 2% up 1 and Independents and others are 12% down 2.

This poll of 1,000 voters has a margin of error of plus or minus 3% and was taken over six days up until last Thursday.

As the campaign has entered the final week, the continued swing to Sinn Féin is significant as undecided voters make up their mind as to who to vote for.

Fianna Fáil’s support has dropped by two points to 24%. It comes as party leader Micheál Martin is planning to keep promising to tackle the problems in housing and health, which he believes are the two key issues for the electorate.

Fine Gael's strategy to focus heavily on the economy and the potential impact of Brexit appears to have backfired as its support has fallen back by a further two points to 21%.

The last time the party was this low in a Red C poll was back in November 2014, in the middle of the water charges controversy.

Fine Gael and Fianna Fáil are both going to likely intensify their warnings about the “risk” of Sinn Féin’s manifesto promises, in the hope of attracting voters who do not want Sinn Féin in government.

The Green Party is down by one point to 7%, but it is still on course to return to Leinster House with up to 10 seats.

Labour's poll rating remains well below the 10% mark but they have increased marginally from 4% to 5% while the Social Democrats are unchanged on 3%, Solidarity-People Before Profit are down by one point to 1% and Peadar Toibín’s Aontú party are up by one point to 2%.