The SDLP and Sinn Féin are calling on the Irish and British governments to order mobile phone firms to introduce all-Ireland tariffs.
The two governments have already given these companies until March to come up with solutions to the problem of people incurring roaming charges in border counties.
The problem sees some people in certain areas being charged international rates because their signals are picked up by transmitters on the other side of the border.
The two main nationalist parties in the North have say all-Ireland tariffs are the best approach, with the SDLP saying the technical solutions suggested by the phone companies would only reduce rather than eliminate the problem.