Procurement competition is expected to continue to put some upward pressure on lamb prices this month.
However, ever-tightening processor margins might limit just how much higher prices could go, Rabobank's latest Agribusiness Monthly report said.
Schedule prices in both islands had been pushed through the $8kg threshold, the highest price recorded for August.
As of the start of August, the slaughter price in the North Island averaged $8.10 cwt (3% higher month-on-month) while South Island lamb averaged $8 (4% higher).
As was normal for this stage of the season, ongoing price lifts were predominantly driven by procurement competition for an increasingly shrinking supply of lambs for slaughter.
The latest available slaughter data - up to the start of July - showed New Zealand's total lamb kill for the season to date remained only marginally ahead of the low numbers seen last season.
However, there was a clear split between the islands. The North Island kill was up 5.7% while the South Island kill was down 1.1%, indicating a greater proportion than normal of the remaining supply would be sourced from the South Island.
Export data for October-June revealed just how strongly New Zealand's lamb exports were performing. Total lamb export receipts for the first three-quarters of this season ($2.6billion) were up 23% on the corresponding period last year, and had already surpassing the total value of lamb export receipts for the entire 2016-17 season ($2.5billion).
The increased value had been driven by improving average export values which, at $10,375/tonne, were 16% higher than last season's average export value. However, season-to-date export volumes were also 4% higher, helping to support the overall increase in export returns.