CSR's sugar and energy business Sucrogen, which includes the Chelsea sugar refinery in Auckland, has been sold to the Singaporean company Wilmar International.
The ABC reports that CSR has accepted a $A1.75 billion offer for Sucrogen.
The deal needs approval from Overseas Investment Offices in both Australia and New Zealand but it is expected the sale will be completed before the end of the year.
Canegrowers in Queensland were not expecting the announcement.
Mackay Canegrowers chairman Paul Schembri says most thought that Bright Foods, which is based in China, was making a play for the company.
He says farmers want assurances that their contracts with Sucrogen are still valid.
Greenpeace finds sale disturbing
Greenpeace says that Wilmar is one of the world's biggest palm oil companies, and one of the worst, and that the purchase may damage the reputation of Chelsea Sugar, which calls itself one of New Zealand's favourite brands.
Greenpeace calls the sale disturbing, saying Wilmar has been involved in the destruction of rainforests.
CSR says it's not worried by that allegation. Spokesperson Martin Cole says that the company is aware of the concerns and that Wilmar has been working to address them.
He says Wilmar has signed up to a sustainable palm oil accord and is upgrading all its plantations to that standard.