Leo Varadkar's personal satisfaction rating also fell by nine points.
Sinn Féin has taken a 10% lead over Fine Gael according to the latest Sunday Times opinion poll.
In the first poll post-
Merriongate, Leo Varadkar's party has seen a decrease to 23%, meanwhile, Mary Lou McDonald's party is up 3% to 33%.
The poll also revealed that overall satisfaction with Government has dropped by four points to 42%.
The Tánaiste's personal satisfaction rating has also fallen by nine points, to 39% as McDonald remains the most popular party leader, with a 48% satisfaction rating.
The poll comes as Fine Gael members Simon Coveney and Leo Varadkar have been embroiled in controversy over recent weeks surrounding the proposed appointment of former Minister Katherine Zappone to a UN Special Envoy role.
Varadkar has also face backlash over his attendance at a
UK music festival during the weekend Electric Picnic was due to take place, before the Irish entertainment sector fully reopens on 22 October.
Last week, Minister for Foreign Affairs
Simon Coveney admitted to creating a "political embarrassment" for Government amid the controversy surrounding the Special Envoy role offered to former Minister Katherine Zappone.
Coveney acknowledged "making mistakes in recent weeks" saying that Zappone was "clearly" trying to establish a career for herself in the UN.
