One of his companies, Tattarang AgriFood Investments, purchased more than 20 million shares in Bega Cheese this week for about A$108 million on New Year's eve.
There is speculation over the ditch that Bega could launch a takeover bid for Fonterra's Australian business, which is under review and could end up on the chopping block.
Bega would have to borrow to pay for an offer for Fonterra, but with Forrest as a cornerstone shareholder, raising the money may not be a problem.