Food-sector unions say Australian employers are using the threat of cheaper labour costs in New Zealand as a bargaining weapon when negotiating with their workers.
James Ritchie of the International Union of Food Workers says it has been told companies in Australia are using the threat of relocating their operations as a bargaining weapon with workers.
Mr Ritchie says this has motivated unions here to work more closely with their counterparts in Australia. He says they will share information and alert each other when a company begins to investigate moving.
However, Business New Zealand says companies are unlikely to relocate solely because of labour costs.
It says wage bills are only one of many factors taken into account when a company decides to move production overseas.