The merger has been on hold for five years following legal moves by Australia-owned carpet maker Godfrey Hirst.
The Commerce Commission said the public benefits of retaining the industry in New Zealand would outweigh the loss of competition. The merger/acquisition would create a national wool-scouring monopoly but, with the industry facing tough competition from China, the commission said the acquisition would help retain the industry in New Zealand.
Mr Alston said the timing of the merger and the number of jobs lost was yet to be finalised.
The merged entity will be 55 per cent owned by Cavalier Corporation, New Zealand private equity firm Direct Capital and the Accident Compensation Corporation, with WSI parent Lempriere Australia taking a 45 per cent stake. Lempriere is majority-owned by a Chinese-based textile group which has an option to increase its share of the merged entity to 72.5 per cent by buying out ACC and Direct Capital.
"This is about protecting the industry," Cavalier Corporation chief executive Paul Alston said.
Australia has no wool-scouring industry, with the nation's clip processed in China.
He would be in Hawke's Bay today to iron out details of the merger.
He said while Cavalier's wool scour was profitable it faced increasing pressure and the merger would "protect its long-term future".
Godfrey Hirst has said prices for scouring services could jump as much as 25 per cent following the merger.
In a statement it said it had considered appealing the latest decision to the Supreme Court but New Zealand's courts were "willing to endorse the regulator's seeming lack of concern at allowing a monopoly to occur in a key primary industry where much of the so-called public benefits will flow to offshore Chinese owners and most of the detriments will be felt by New Zealand farmers".
The Awatoto wool scour is across the road from Cavalier Corp's spinning plant, which brought 39 new jobs to Hawke's Bay earlier this year following the closure of Cavalier's Whanganui's spinning plant.