Labour leader Ed Miliband demanded changes in the wake of the controversy over Unite's role in the selection of a party candidate for the Falkirk seat in the next Westminster election.
Mr Miliband wants to reform the link, which currently sees union members automatically enrolled into the party, with a special conference planned on March 1 aimed at voting on the changes. He wants members to actively opt-in.
The Trade Union and Labour Party Liaison Organisation - which represents the unions affiliated to Labour - will meet in London.
Lord Collins, a former Labour party and union official, has been consulting with union officials for months in a bid to reach agreement. Talks are likely to continue to try to reach a deal before the March 1 conference in London.
The GMB has already decided to drastically cut its funding of Labour in protest at the reforms, and other unions could follow suit if there is no agreement.