A Brisbane fertiliser plant operated by Incitec Pivot will remain open until at least the end of 2022 after signing a new gas supply deal, securing more than 400 jobs.

The Gibson Island plant uses gas as a feedstock to produce industrial chemicals and fertilisers, distributing to more than 4000 cotton, sugarcane and sorghum farmers in Queensland and northern New South Wales.

Incitec Pivot CEO Jeanne Johns says the plant had faced closure by the end of 2019 due to rising gas prices and securing the new gas supply agreement provided a secure future for workers.