Wellington, July 5 NZPA - Fruit and vegetable growers say they want an independent investigation of the retail pricing of their produce, in the wake of evidence that growers are not getting paid any more for produce than they were five years ago.

"There are times when the prices paid to growers, and the prices paid by consumers, appear out of line, and potentially someone is losing out," Horticulture NZ chief executive Peter Silcock said today.

"The fact is, our growers are struggling to cope with a cost price squeeze that is reducing real returns".

"Growers and consumers alike need to be confident there is enough transparency in the pricing system to ensure a consistent and acceptable mark up range, rather than the extremes we see now".

As a general rule retail prices were between 100 percent and 200 percent higher than the wholesale price, but sometimes it could be much higher, Mr Silcock said.

An independent investigation, perhaps led by Justice Minister Simon Power, could explain where the costs are in the supply chain, and where the profits were going.

But a spokeswoman for Horticulture NZ said tonight that growers would have to be offered some sort anonymity for their testimony to avoid their produce being blacklisted by supermarket chains

In Britain, an initial supermarket code of practice introduced in 2002 to redress the balance between the big supermarkets and their suppliers -- including vege growers -- proved too weak.

A two year-inquiry by a competition commission later reported that supermarkets' abuse of buyer power had an adverse effect on competition against consumer interests.

In February, the UK Government said it would appoint an ombudsman to enforce a new conduct code for supermarkets, and to curb abuses of power.

Horticulture NZ would support discussion of a New Zealand code of conduct for retailers and others in the supply chain, the spokeswoman said.

New Zealand Food and Grocery Council (FGC) chief executive Katherine Rich said the British code of practice for grocery retailers "could have application in New Zealand".

"We are interested to see whether such a (British) initiative makes a positive difference before formally endorsing the concept for New Zealand," said Mrs Rich, a former MP.

In the United Kingdom the concept was backed by both the Tory and Labour politicians and had wide political support, but there were some differences between the two countries.

She suggested that "on the whole" retailer/supplier relationships in New Zealand were more positive than in Britain and that long-term business relationships were seen as important by grocery executives.

"The executive teams of both supermarkets work extremely hard to cultivate good supplier relations," Mrs Rich said. "However, there will always be individual cases where a clear code might provide useful guidance".

But Horticulture NZ said any code of practice designed to promote fairer dealing between supermarkets and their suppliers, and prohibit the biggest food retailers from unfair buying practices would only be effective with good and independent enforcement. Policing a conduct code would need a tough watchdog, but growers had not yet given consideration to who might fill such a role.