Fonterra has previously forecast that it expects low prices to translate into a 6 per cent decline this 2015/6 season and data released yesterday showed production was in line with that forecast.
The co-op's milk collection across New Zealand in December was 3 per cent lower than last year. For the season to December 31, it reached 932 million kg - 4 per cent behind the period last season.
Fonterra said the lower production was largely the result of a low milk prices, where farmers have reduced stocking rates and supplementary feeding to reduce costs.
North Island production was down 6 per cent in the season to date and was down by 1 per cent in the South Island. Australian production was flat in the season to date.
ANZ rural economist Con Williams said the market could struggle to improve from here.
"Anecdotal feedback suggests that buyers are relatively comfortable with their inventory positions at the moment, and think that with perhaps an improvement in New Zealand seasonal conditions that they are going to be less willing to build stock," he said.
The US Department of Agriculture expects the familiar themes of oversupply and low demand to persist this year, and that it did not see prices improving in the first half.
The department said milk production during 2015 among the world's major suppliers is estimated to have expanded by 1 per cent over the previous year, sharply down from the 4 per cent growth seen in 2014.
For the current year, low milk prices are expected to restrain growth in milk output, which it expects will decline in Oceania but will increase in the EU, Argentina and the United States.
"Although the pace of increasing milk production is forecast to slow, prices for such dairy products as skimmed milk powder and whole milk powder are expected to remain relatively weak," the USDA said.
These products face strong headwinds due to the continuation of the Russian ban on imports of dairy products and weak import demand from China.