Opus Group's private equity backer has taken control of the company after more than doubling its shareholding.

Knox Investment Partners now controls 69.5% of Opus after it converted a high-interest loan into equity.

The Auckland firm loaned Opus $2.4 million at 15% interest in March.

Knox previously held a 30.7% stake in the company, according to Opus' 2012-13 annual report.

Knox managing director Tim Sumner said the firm backed Opus' ongoing restructure.

"Opus Group has been operating in a challenging macro environment over the last 12 months but we believe the group is well-positioned for the future," he said.

The group's other major shareholders are Opus executive director Richard Celarc, who holds 14.6%, HSBC Custody Nominees with 6%, Takatimu Investments with 4.3% and Opus chief executive Cliff Brigstocke with 3.2%, according to the annual report.

[Related: Ups and downs of Opus]

Comment below to have your say on this story.

If you have a news story or tip-off, get in touch at editorial@sprinter.com.au.  

Sign up to the Sprinter newsletter