"The consultative process provided new information about risks of some of the originally proposed changes to regulated milk - particularly for downstream markets and consumers," Mr Guy said in a statement.
"The Government is therefore deferring the consideration of those potential changes to regulated milk for Goodman Fielder and small or domestically focused processors."
In 2015, independent processors collected 22% of all milk solids in the South Island and 9% in the North Island, triggering the expiry of the provisions in the South Island by no later than May 31, 2018.
The Commerce Commission was tasked with investigating whether Fonterra's 86% share of the local market gives it too much dominance as part of the legislation governing the sector, and found there still was not enough competition to warrant full deregulation.
Mr Guy dropped the market share thresholds to trigger a new review of the act, instead adopting the need for a review in 2020/21.
If the minister deems the regime needs to stay in place, another report on competition will have to take place within the following five years.