"We look forward to working with Goodman Fielder and its management team to improve Goodman Fielder's performance over time," Wilmar's chairman and chief executive Kuok Khoon Hong said.
Wilmar said the purchase was funded internally.
Shares in Goodman Fielder shot up by almost 30 per cent in New Zealand after Wilmar declared an initial 5 per cent interest and that it wanted to take it to 10 per cent.
By 3.20pm the stock was trading at $0.85, up 18c from Monday's close, having earlier hit $0.87 - its highest point in almost six months.
Wilmar is one of Singapore's largest listed companies by market capitalisation.
Its business activities include oil palm cultivation, oilseeds crushing, edible oils refining, sugar, specialty fats, biodiesel manufacturing and grains processing.
The company makes and distributes fertilisers, owns a fleet of vessels and is one of the largest plantation companies in Indonesia and Malaysia.
The group's net profit for 2011 came to US$1.6 billion, up 21 per cent on the previous year's.
Goodman Fielder New Zealand (GFNZ) is Goodman Fielder's sole operating company in New Zealand and is the largest consumer food supplier in this country.
GFNZ's brands include Quality Bakers, Nature's Fresh, Meadow Fresh, Tararua, Edmonds, Irvines, Champion, Chesdale and Huttons.
Earlier this month, Sydney-based Goodman Fielder reported a 77 per cent slump in its first-half net profit to A$21.5m ($27.7m) from A$93.1m a year earlier.
The company said then that it had received unsolicited interest in its Integro food ingredients business and the New Zealand milling operations.
The milling operations, which include Champion flour mills in Christchurch and Mt Maunganui, had goodwill, brand and licences valued at A$49.8m in the 2011 annual report, while the Integro goodwill, brand and licences were worth A$10.7m.
