Senior Labour party officials have agreed to allow their members in Northern Ireland to organise politically.
Trade unionist Andy McGivern challenged Labour rules
However, the full details of the move will not be published for a month.
Local trade unionist and party member Andy McGivern, a long-time campaigner on the issue, said it was a significant step forward.
"What it means is that we will have an input into the policy-making decisions of the party," he said.
"Certainly, that is something that has never been the case for anyone in Northern Ireland.
"We couldn't influence policy, we couldn't influence ministers. Now we will be able to do so."
Mr McGivern said he met party officials on Tuesday evening and agreed terms for dropping a court case against the party.
A previous case brought by Mr McGivern under equality legislation forced Labour to allow people in Northern Ireland to join.
The details of the latest agreement will have to be put to an internal Labour committee and will not be published until October
It is understood, however, that Labour will set up a local forum in Northern Ireland once 200 members have joined.
The forum will have the right to send delegates to the Labour conference and submit motions for debate.
It is believed the agreement does not cover the question of Labour members fighting elections in Northern Ireland.