The Road Transport Forum says freight rates for livestock transport operators have to increase if companies are to survive.
A five-yearly survey carried out for the forum has revealed that the whole road freight industry is under financial pressure.
Chief executive Ken Shirley said North Island stock transport firms are the worst affected with a return on capital of minus 4.5 which means firms are using up capital and won't be able to stay in business long term.
Mr Shirley said some companies have folded and others have amalgamated or been bought up.
"It's very tough, very competitive," he said. "The only solution is to have higher freight rates."
Mr Shirley said there reports that financially-stressed transport operators have been breaking rules such as overloading trucks, speeding to meet tighter schedules and breaching work-time conditions.
He said the Road Transport Forum does not condone any of that and its livestock transport safety committee will be discussing those sorts of issues.