Dairy product prices fell by 3.9 per cent at this morning's Global Dairy Trade auction - the fourth decline in a row.
The price of wholemilk powder - which has the greatest bearing on Fonterra's milk price - fell by 4.2 per cent to US$2797 a tonne - its lowest point in more than a year.
Among the other Fonterra reference products, skim milk powder fell by 8.1 per cent to US$2527 a tonne.
Against the trend, butter prices rose by 0.3 per cent to $4144 a tonne.
Anhydrous milk fat rose by 1 per cent to US$4331 a tonne.
• Dairy prices rise at first Global Dairy Trade sale for 2020
• Global dairy prices feel the coronavirus bite
• Whole milk powder leads drop in dairy auction prices
• Dairy prices go beyond market expectations at GDT auction
Rabobank said onset of coronavirus stalled the upward trajectory in global dairy prices visible in late 2019 and the hangover had continued.
The GDT Price Index moved lower by 4 per cent with average prices now sitting below US$3,000/tonne.
"Buyers and sellers are still scrambling to assess the market impact as the spread of the virus moves from China to more broadly across the globe," the bank said.
Outside the reference products, cheddar prices rose by 2.6 per cent to US$4398/tonne and rennet casein rose by 1.0 per cent to US$9987/tonne.
In February, Fonterra reaffirmed its farmgate milk price and earnings forecasts for the year, despite uncertainty surrounding the outbreak of the coronavirus Covid-19 in China.
The co-op said its farmgate milk price forecast range would remain at $7-7.60 per kg and its full-year underlying earnings guidance would stay at 15-25 cents per share.
However, Fonterra revised its forecast milk collections for the 2020 season down from 1530 million kgMS to 1515 million kgMS, due to adverse weather.
The co-op is due to report its first-half result today at 8.30am.