Fonterra is still by far the biggest cheese in New Zealand's raw milk market with the latest figures showing its processing rivals have yet to make a real fight of the big cooperative's 17-year reign.

Given the growth and geographic expansion of privately owned dairy companies Open Country and Synlait, industry observers had expected Fonterra's hold on the raw milk collection market to have slipped under 80 per cent last season, as competition increased for flat-lining national milk production.

The farmer-owned cooperative started life in a 2001 industry mega-merger with 96 per cent of the market, enabled by special legislation.

But new DairyNZ figures show Fonterra's raw milk market share in the recently ended 2017-2018 season was 81 per cent, just a shade lower than the 82 per cent share recorded the previous season.


Observers suggest that Fonterra's market share has not slipped as steeply as expected despite widening criticism of its financial performance and investment decisions and the growing strength of competitors, because some of its farmer-owners have increased their individual milk production even while national production peaked.

The market share of the country's second biggest dairy export processor Open Country Dairy rose from 7.1 per cent to nudge 7.5 per cent last season, while listed Synlait Milk and the cooperative Westland were next, each posting a share of 3.4 per cent.

Next in line was Miraka with a 1.4 per cent share and Oceania Dairy with 1.1 per cent, according to DairyNZ. Blue chip Waikato value-add cooperative exporter Tatua collected .07 per cent of all New Zealand milk.

A report in April by dairy industry specialty analysts TDB Advisory suggests Synlait's market share has fallen slightly from TDB's 4 per cent in 2017, while Westland's has crept up from 3 per cent.

The market shares of Miraka, Oceania and Tatua remain largely unchanged from 2017.

TDB's report said milk production volumes had grown by 52 per cent or around 470 million litres a year between Fonterra's formation in 2001 and 2017.

While Fonterra's market share had fallen over this time its milk volume collection had increased by 37 per cent, said TDB.

"With Fonterra collecting over 300 million litres of the average 470 million litres of new milk per year, the remaining 170 million litres have been going to Fonterra competitors," said TDB in its April report.