THE SOCIAL Democratic and Labour Party (SDLP) has confirmed it will form the official opposition at Stormont.
The party has written to the assembly Speaker informing him of the move.
Following disappointing election results in May, the party lost its right to nominate a minister to the executive.
Party leader Colum Eastwood said he has formally nominated South Belfast assembly member Matthew O'Toole to lead the opposition.
Mr O'Toole has encouraged other parties, particularly the Alliance Party and Ulster Unionist Party (UUP), to join the SDLP in forming an opposition.
“Our first act as an Official Opposition will be to recall the Assembly this week to end the deadlock that has gripped our institutions and paralysed government from taking the decisions needed to address the cost of living crisis facing every household in Northern Ireland," O'Toole said.
"Those who have held the democratic institutions of the Good Friday Agreement to ransom cannot be allowed to inflict further pain on our communities while they play cynical power games in London. No more letting them away with it.
“The SDLP has a plan, we have a fully drafted emergency bill that could unlock the millions of pounds resting in Stormont Ministers’ bank accounts and instead put it directly into families pockets. It’s long past time that Ministers collecting their wages, showed us exactly what the public are paying for. The pretence of governing, while delivering nothing for people and communities must end."
The party will also gain extra speaking rights in the Assembly chamber and will be the first in line to question ministers.
It will also be entitled to hold the chair of the key scrutiny body the Public Accounts Committee and it will be able to set the agenda in the Assembly for 10 days per year.