Product prices were mixed at the Global Dairy Trade auction amid lower appetite for milk fats.

The GDT price index fell 0.5 per cent from the previous auction two weeks ago, its first decline since early September.

The average price was US$3467 a tonne, compared with US$3481 a tonne two weeks ago.

Some 36,258 tonnes of product was sold, down from 37,968 tonnes two weeks ago.

"The decrease was driven by reduced demand for milk fats which offset strong prices continuing for milk powders" NZX dairy analyst Robert Gibson said in a note.

Whole milk powder rose 0.1 per cent to US$3,331 a tonne. It's the highest average price in three years, according to Gibson.

"Although prices softened a little for January to March delivery dates, these were offset by strength in prices for dates further out" Gibson said.

Rennet casein rallied 4.9 per cent to US$8,047 a tonne, while cheddar climbed 2.7 percent to US$3,797 a tonne.

Skim milk powder rose 1.9 per cent to US$3,068 a tonne.

That "is the highest average price since August 2014, continuing the strength seen in this commodity during the previous six GDT events" according to Gibson.

Butter milk powder advanced 1.6 percent to US$2,846 a tonne.

Lactose was at US$779 a tonne; no percentage change was given.

Meanwhile, anhydrous milk fat dropped 5.1 per cent to US$4,840 a tonne, while butter fell 4.9 per cent to US$3,983 a tonne. For both anhydrous milk fat and butter, prices decreased across all delivery dates, Gibson noted.

For sweet whey powder, no product was offered or sold, or no price was published for the last event, or on both of the two previous events.

There were 135 winning bidders out of 179 participating at the 15-round auction. The number of registered bidders was 516, up from 514 at the previous auction.

- BusinessDesk