Stacy said sheep farmers had enjoyed 18 months of stability, which was setting them up well for next season.
Next season's lambing percentages were also expected to be high, she said.
ASB, in its latest commodities report, said lamb were strong across key markets and reflected generally healthy global economic growth and demand.
US and EU - excluding the UK - prices were particularly strong.
"EU prices for the season to date sit 22 per cent higher than for the same period a year ago, while US prices are up 19 per cent," the bank said.
These increases compared to the overall 16 per cent in New Zealand lamb export prices.
"Looking ahead to the new season, we are optimistic that prices will remain very healthy, but at the same time we are wary of growing risks," the bank said.
In particular, the escalating US-China trade tensions could derail global economic growth and reduce global lamb demand.
"The other risk is that consumer price resistance can kick in at these record levels," the bank said.