NORTHERN NSW is running behind the rest of the state in construction because of collateral damage from the bust of south-east Queensland's property market, according to a housing boss.

GJ Gardner Homes NSW director Matthew Hope said business was stable across the state, but northern NSW was affected by the slow south-east Queensland property market.

"Across NSW the numbers haven't been too bad," he said.

"We're pretty certain that it's going to be flat market for the next 12 to 18 months."

Mr Hope was at the Tweed Heads offices yesterday to discuss the extension of the Tweed office's territory to Grafton after terminating the Ballina franchisee's contract.

The termination of C & E Structures' licence was for breaching its contract.

"The Tweed office will continue as usual," Mr Hope said.

"The office's exclusive area is still in the Tweed. Our goal is for the Tweed office to work with our current clients."

Mr Hope said the franchisee model was strong and there was high demand from builders wanting to work with GJ Gardner Homes.

"We have had a really good relationship with the franchisees," he said.

"This (terminating a contract) is the first time I have had to do it in six years.

"Our franchisee network has asked us to be stricter with the rules.

"The model does work and it's a good thing that our customers have overarching support and not solely dealing with individual builders."

The Tweed franchisee did not want to comment.