Westpac Banking (ASX:WBC, NZE:WBC) said it is forecasting commodity prices excluding gold, to fall in the coming quarters as intense volatility around US tariffs, as well as retaliatory measures, has been challenging, it said in a report on Tuesday.

Stronger gold prices lifted the year-end target for the Westpac Export Price Index to 283. Westpac's broad index fell 2.2% in the month with Brent down nearly 13% since April 2.

The financial services firm predicts gold prices to rise to $3,190 per ounce in the June quarter, and then to $3,200 per ounce in the September quarter, before falling to $3,130 per ounce in the December quarter. It expects the gold price to fall below the $3,000 mark in the September 2026 quarter to $2,980 per ounce.

The prices of aluminum and copper are expected to fall to their lowest level in the December quarter at $2,810 per tonne and $8,400 per tonne, respectively.

The aluminum price is forecast to rise to $2,930 per tonne in the December 2026 quarter, and then to $3,010 per tonne in the March 2028 quarter. The price of copper is expected to bounce up to $9,180 per tonne in the June 2026 quarter, and then rise to $10,060 per tonne in the June 2028 quarter.

Westpac anticipates the price of nickel, lead, and zinc are expected to reach their lowest point in the September quarter, at $13,900 per tonne, $1,840 per tonne, and $2,530 per tonne, respectively.

The nickel price is forecast to rise to $15,100 per tonne in the September 2026 quarter and then jump to $16,000 per tonne in the December 2028 quarter. The lead price is expected to climb to $2,000 per tonne in the December 2027 quarter. The price for zinc is forecast to reach $2,750 per tonne in the December 2026 quarter.

It forecast Brent crude oil futures to fall down to $62 per barrel of oil in the September quarter, before rising in the succeeding quarters to $71 per barrel in the September 2026 quarter.