"I can not go into government with Arlene Foster, in the position of first or deputy first minister, whilst there is a cloud hanging over her", the SF leader said.
Sinn Féin will again be the largest party in nationalism in the next Assembly if the power-sharing institutions can be resurrected.
The former first minister said he believes a major negotiation of the kind Sinn Féin is seeking can not be completed in the time legally available before a fresh election should be triggered.
"If they can't get through this election with a result that restarts the power-sharing agreement, they face the prospect of being run from London directly - which nobody wants", Al Jazeera's Laurence Lee, reporting from the capital, Belfast, said.
But under the Northern Ireland peace dea, elections must lead to coalition talks between the largest unionist and nationalist parties which will nearly certainly be the DUP and Sinn Fein and its far from clear if returned they will be able to work together once more.
Observers predict a similar outcome to the May 2016 assembly elections, in which the Protestant and conservative DUP won slightly more seats than the Catholic and socialist Sinn Fein.
The Irish nationalist Sinn Fein party secured two seats in early counts, and is expected to be the second-largest party.
The number of seats up for grabs in the Northern Irish Assembly has been reduced from 108 to 90, with the number of MLAs being determined by the single transferable vote system, a form of proportional representation.
Many voters say they are fed up with sectarian bickering and plan to stay at home in a province where turnout has fallen at each of the last four elections to the lowest level among the United Kingdom regions.
The Green Party leader, Steven Agnew, also enjoyed a vote increase, although remains short of the vote quota.
Irish Taoiseach Enda Kenny has said he will seek an agreement in Brexit talks for Northern Ireland rejoining the European Union, if the voters seek that option in future.
The lead-up to the snap election has been a fractious one, with leaders of the main parties engaging in a tense television debate on Tuesday, including new Sinn Fein head Michelle O'Neill.
Throughout the election campaign, Foster has appealed for unionists to resist Sinn Fein's demands for her to stand aside pending an investigation into the energy scheme. Failure to do so could see the return of "direct rule" over the province by the British government at Westminster.
US Dollar Rises To 7-Week High
The primary reason for EUR/USD's fall on Tuesday night and Wednesday was the increased strength of the US Dollar. Yellen did not directly address the likely impact of theTrump administration's economic policies in her remarks.