Fresh calls were made today for the British government to introduce a cap on new rates to protect low income households in Northern Ireland.
Former Stormont finance minister Mark Durkan said a cap would make the new system fairer for people who can not afford to pay.
Rates bills are currently being calculated according to the value of a property in January 2005.
More than 7,000 homeowners already challenging the rateable estimates of their homes, while 175,000 low income homes will pay reduced or no rates at all.
Finance Minister David Hanson has defended the new rating system, which will be based on the capital value of properties. He has insisted that introducing a cap would benefit a tiny percentage of people at the expense of the majority of ratepayers.
The SDLP leader said a cap would protect people from hardship.
"The fact is the measures David Hanson is imposing are going to put people in to real hardship, they are going to force people to move from their homes," he told BBC Radio Ulster.
"No tax can be fair that is forcing people to moving from their life long home. It is simply wrong.
"It is a cruel tax which cannot be justified, and if a cap is a way of stopping that, fair enough."
Hundreds of people this week protested at meeting in south Belfast called by the recently formed Northern Ireland Fair Rates Campaign.
The group had urged the Government to introduce a cap on bills. However, the Government has stood firm against growing public and political opposition to the introduction of the planned new rates system.