Fresh disagreements over policing and justice have plunged the Northern Ireland Executive into crisis, it was claimed tonight.
Sinn Féin warned at the weekend that it will collapse ministerial power-sharing arrangements if security responsibilities are not devolved to a local minister.
The Democratic Unionist Party (DUP) said the comments were not constructive or helpful.
David Ford's Alliance Party has been mooted as a candidate for the position.
"This illustrates the ongoing crisis, the fact that there is so little meeting of minds between the DUP and Sinn Féin, it isn't a brilliant example of partnership Government," said Mr Ford.
Sinn Féin's Dáil leader Caoimhghín O' Caolain told supporters at a republican commemoration in Co Cavan that his party's patience should not be tested.
"The power-sharing government in Northern Ireland was established after the St Andrews talks which envisaged transfer of policing powers by May, but unionists ruled this out as being too early.
Mr Ford added: "This (Sinn Féin statement) suggests a lot of work to be done around the whole issue.
"What is clear is there's a degree of unhappiness."
Sinn Féin first highlighted its growing frustration in June when it seemed poised to derail the election of DUP leader Peter Robinson as the North's First Minister when he took over from Ian Paisley.
After crisis talks involving British prime minister Gordon Brown and the Irish Government, the DUP and Sinn Féin committed themselves to intensive negotiations.
The DUP and Sinn Féin, the two largest parties in the North, dominate the Executive and a number of its meetings have been cancelled as a result of the Sinn Féin/DUP split.
While some progress has been reported on the transfer of policing powers, the issue remains unresolved and the parties are still divided on other matters, including the creation of an Irish Language Act and the future of the Maze prison site.
DUP junior minister Jeffrey Donaldson has said his party was committed to finding a resolution to the deadlock, but added the comments by Sinn Féin questioned its commitment to making progress at Stormont.