Company secretary Wayne Butler said that historically, the Hill family shareholding had been held in a number of different family trusts.
"The Hill family advises that the reasons for doing so are no longer relevant and it considers that a single entity is now more appropriate."
The family also wanted to increase its shareholding in the company to about 50.1% from the 48% it currently held in MHI, he said.
The matter would be put before the company's annual meeting on November 5.
If the move was approved by shareholders, the Hill family would increase its percentage voting control in the company by buying shares on the market in a manner broadly similar to a company share buy back in the 12 months following approval, Mr Butler said.
Forsyth Barr broker Suzanne Kinnaird said it was difficult to know what the thinking was behind this move.
"Maybe they just view the company as a good investment. They effectively have a controlling stake now, although technically this move gives them absolute control."
By consolidating into one holding, and having 50.1% of the company, it would make it simpler for the family in the future should they decide to hand control to another party - although that did not seem likely in the near-term, Ms Kinnaird said.
MHI shares rose 4c to 69c yesterday.
