The delay over the devolution of policing and justice continued yesterday, as the DUP and Sinn Fein failed to agree on what the phrase “at all times” means.

An Assembly Committee considering draft proposals from First Minister Peter Robinson and Deputy First Minister Martin McGuinness became deadlocked after their parties offered conflicting interpretations of the devolution blueprint.

The committee adjourned its discussions but the SDLP said the public dispute exposed continuing divisions between Sinn Fein and the DUP.

The Assembly and Executive Review Committee was examining proposals for establishing a ministry in the event of the two main parties agreeing to the devolution of policing and justice powers from Westminster to Stormont.

The row comes as the DUP and Sinn Fein are involved in talks aimed at settling the dispute over the issue that has prevented meetings of the Executive for four months.

In July Mr Robinson and Mr McGuinness confirmed they had agreed a format for the new ministry and asked the committee to compile a report on the proposals.

The pair decided that neither the DUP nor Sinn Fein would hold the post and signalled that it would be filled through a cross-community vote of the Assembly, with speculation that the Alliance Party would emerge as an agreed candidate.

The SDLP objected to the DUP/Sinn Fein plan to select the Justice Minister by use of a cross-community vote in the Assembly which simply required a majority of nationalists and a majority of unionists to back a proposed candidate.

The SDLP claimed this would effectively give unionists the power to permanently block a nationalist ever holding the post.

In the latest development, committee members clashed yesterday over a phrase in a July letter from Mr Robinson and Mr McGuinness which said a Justice Minister would be elected in such a fashion “at all times”.

The DUP said this meant the new voting arrangement would be permanent, while Sinn Fein claimed it referred only to the life of this Assembly.

Mr Robinson said: “The evidence is there for all of you to see.

“I would like to hear anyone put any other meaning to the letter than the meaning, there's no other possible outcome.

“For all time there would be the requirement that there's cross-community support for the justice minister.

“Why would you want a justice minister that could not get the support of our whole community?”

A Sinn Fein spokesman, however, said the letter merely noted that any justice minister would be elected “at all times from the Assembly” to rule out suggestions that a high profile public figure from outside the ranks of the 108 Assembly members would be brought in to fill the ministry.

“None of those DUP members who sit on the committee were involved in the drafting of the letter,” the Sinn Fein spokesman said.