Severe feed shortages in parts of the country mean many ewes are on a nutritional knife-edge heading into lambing and could be at risk of developing metabolic disorders.
The National Council of New Zealand Wool Interests has made the maximum allowable weight restricted to 200kg.
The council comprises associations and organisations involved in the domestic and international trading of greasy and scoured wool. It acts as the New Zealand member of the International Wool Textile Organisation, which represents the interests of the wool textile trade at the global level.
"The National Council and its members are committed to providing a safe working environment throughout the wool industry," the council says in a statement
"Increasing concerns relating to bales weighing over 200kg (which are estimated to cover approximately 6% of the national clip) have prompted the council to address the issue.
"Bales weighing in excess of 200kg can contribute to workplace accidents and throughout the industry provide a significant problem during dumping and shipping. These bales have been assessed as hazards during transport and handling, with changes deemed necessary to comply with tougher Occupational Health and Safety laws being introduced in New Zealand.
"The New Zealand Wool Brokers Association and the Federation of Private Wool Merchants have been actively promoting the new bale weight limits to growers through their respective newsletters. Woolgrowers are encouraged to comply with the new bale weight limit to minimise any re-packing and additional charges that may be incurred."