Advertising watchdogs have thrown out a complaint about billboard liquor lobbying in Eden-Roskill, but warned supermarket owners to identify themselves during their anti- licensing trust campaign.

Around 63,500 electors in these two Auckland districts are voting in a postal ballot on whether to allow liquor sales in the newly "wet" areas to be controlled by a licensing trust.

Progressive Enterprises, which owns Foodtown supermarkets, has been urging residents to vote against a trust, saying it will mean they will be unable to buy wine or beer at local supermarkets.

Trust supporter David Jacobs complained about billboards put up around the district by Progressive Enterprises, saying they were misleading and did not identify who had paid for them.

Mr Jacobs' pro-trust campaign is being paid for by the New Zealand Licensing Trusts Association.

The Advertising Standards Complaints Board yesterday announced its decision on the billboards, rejecting Mr Jacobs' claims.

It did, however agree with Mr Jacobs that Progressive had breached rules governing "advocacy advertisements, which state the identity of the advertiser must be made clear.

Progressive was told exactly this in 1997, when it launched a similar campaign against trust control of liquor sales in Grey Lynn.

"In this instance the Chairman considered it important to reiterate that it was incumbent of advertisers to ensure that previous decisions of the Board were followed and not disregarded."

Progressive is now putting stickers on the bottom of its billboards, saying they are responsible for them.

Returning officer for the poll, Dale Ofsoske, said 17,116 of the 63,522 voting papers sent out to electors had arrived back.

This was a turn out rate of 27.8 per cent in Roskill and 24.5 per cent from Eden. The last time a licensing trust vote was held in Auckland was in 1997, when Grey Lynn voted against a trust, on a 53 per cent turnout.

Voters have until 5pm on Friday, March 17 to get their papers back to the returning officer.

Mr Ofsoske said some voters had contacted the returning office, needing clarification about exactly what the ballot paper was asking them to decide.

"If electors vote against establishment of a trust then the area goes truly "wet", which means anyone entitled to hold a liquor licence may apply for such a licence in the area."

"If they vote for a licensing trust, then hotel, tavern and bottleshop outlets, with the predominant purpose being the sale, supply or consumption of liquor, must be operated by a licensing trust."

There are some exceptions, for places like restaurants and sports clubs.