SINN Fein and the SDLP have proposed creating a Stormont committee to address the displaying of flags and other contentious symbols at Parliament Buildings.
The two parties yesterday tabled a joint motion calling for an ad hoc group to discuss the issue of flags, emblems, symbols and language.
In the aftermath of Belfast City Council's vote to fly the Union flag on designated days only, the DUP and UUP have sought to use the Assembly Commission to overturn Stormont's flag policy.
For the past decade the flying of the Union flag over Parliament Buildings has also been restricted to designated days.
Since December, Sinn Fein, the SDLP and Alliance had thwarted the unionist parties' efforts by boycotting Assembly Commission meetings.
However, earlier this month Alliance MLA Judith Cochrane rejoined the commission, which last week agreed to report on a review of Stormont's flag flying policy.
Alliance insists the commission's involvement has no predetermined outcome.
But Sinn Fein and the SDLP are adamant that the Assembly Commission - Stormont's administrative body - is not the place to deal with flags and other symbols.
"As agreed in 2000 by the Assembly Commission, flags and other such matters are political and best handled in the assembly," Sinn Fein MLA Caitriona Ruane said.
The South Down representative said bringing the issues into the debating chamber would ensure "parity of es-teem, equality and diversity are best served" and leave the commission to "get on with its role of managing Parliament Buildings".
"The debate will be heard in the proper venue and it is hoped that there will be political leadership shown and we call on all parties to support the motion," Ms Ruane said.
Pat Ramsey of the SDLP also claimed other parties were seeking to have flag policy addressed by the Assembly Commission even though such matters were not in its remit.
"The SDLP is firmly of the belief that the issue of flags shouldn't be for the Assembly Commission but for the assembly to debate," he said.
"The commission previously used guidelines issued by the NIO and for 10 years there was no dissent."
Mr Ramsey added that the "only semblance of nationalism" at Parliament Buildings was the portraits of two former deputy first ministers - Mark Durkan and Seamus Mallon.
The assembly is expected to debate the motion in two weeks' time. ■ DESIGNATED DAYS: The Union flag is raised over Belfast City Hall last month to mark the Duchess of Cambridge's birthday