Canterbury dairy syndicate Synlait is appealing an Environment Court decision over priority to take water from the Rakaia River.
Earlier this month the Environment Court ruled the Central Plains Water Trust had priority over Synlait, a decision that surprised the dairy co-op.
Synlait wants the water as part of a scheme to irrigate 6,000 hectares of farm land, while the trust wants access to the water as part of its $350 million irrigation scheme.
Synlait developments manager Ben Dingle says an appeal has been lodged in the High Court in Christchurch.
He says Synlait would not take legal action if it did not have
confidence in a successful outcome.