On Friday, chairwoman Anna Rawlings said in coming to its decision the commission had focused on whether the price of single-day, multi-day and season ski passes would increase with the acquisition.
It also considered the extent to which an alternative buyer would invest in, and develop, the Treble Cone skifield.
Ms Rawlings said it was satisfied the acquisition was "unlikely to substantially lessen competition".
"The merged entity would be unable to successfully charge higher prices, or reduce the quality of the services offered, due to the high numbers of skiers from outside the region with alternative options.
"We are satisfied that there is unlikely to be a material difference in the extent to which Treble Cone competes," Ms Rawlings said.
Cardrona general manager Bridget Legnavsky said the company was "very excited" to receive the approval.
"We’re now working with Treble Cone Investments Ltd to complete the transaction."
Cardrona has already said if it acquired Treble Cone its priority was to improve the reliability of the field by investing in its snow-making capability and stabilising its power supply.
