New Zealand Grocery Commissioner Pierre Heerden said he has put supermarkets on notice that they should not seek additional margin from rising costs linked to the Middle East conflict, and that any price increases should be reversed as soon as possible, according to a Wednesday RNZ report.

Heerden said supermarkets had indicated that the additional costs had not yet been passed on to consumers, though he cautioned that this would depend on how long the conflict continued, the report added.

Gemma Rasmussen, Consumer NZ's head of advocacy, said that New Zealand should consider an excessive pricing regime similar to one in Australia, which would cap supermarket markups and impose penalties of up to AU$10 million for breaches.

Shares of Woolworths Group (ASX:WOW), which has operations in New Zealand, were marginally higher in recent Wednesday trade.