The value of New Zealand lamb exports dropped 40 percent in August compared to August last year, AgriHQ says.
Analyst Susan Kilsby said the drop in value of $75 million was being driven by the UK market.
"The lamb exports to the UK halved in value in August and that market has really been affected by a lack of demand and also the weaker British pound.
"So the average price of lamb exported in August was slightly higher than July, but it is certainly well below the five-year average."
Ms Kilsby said prices in the UK market dropped by $1.60/kg compared to August last year, and the value of chilled lamb in the UK declined by $4/kg.
"Chilled lamb shipments to the UK market are now at their lowest point we've seen in recent years and the export price typically peak in October, underpinned by the high value of the product that's destined for the Christmas market.
"But with the UK market underperforming and the currency working against our New Zealand exporters we really expect average lamb export values will continue to lag behind historical levels for this peak period."
Ms Kilsby said this flowed on to New Zealand farmers.
"Farmgate prices aren't particularly high at the moment - you typically see them peaking through that October level - so we're not expecting prices at farmgate to be high this year either."