Hundreds of Hamilton property owners will today learn whether they could be blocked from making any changes to their homes if they are close to high-voltage transmission lines.

A letter from Hamilton City Council will arrive in about 450 letterboxes and comes a week after elected representatives and residents angrily spoke out about receiving vague and generic letters informing them their properties had a flood risk.

Some city councillors have slammed both processes as "premature, irresponsible and alarmist" and are shocked it has happened so quickly after they criticised last week's letters.

But Hamilton City Council city planning manager Robert Hodges said the latest letter was about the proposed rules aimed at protecting the transmission corridors. It was in the consultation stages and residents would have plenty of chances to give feedback and make submissions on the plans. While the council was legally required to put in rules, he said details were up to the council.


Under the district plan review of the high-voltage lines, the 450 homes near the corridor will be classed as being in corridor A, which is between 12m and 32m from either side of the transmission centre line, or corridor B, which is within 12m.

The most significant restrictions will be imposed on corridor B properties and could prevent any development, while those in corridor A would need resource consents for any alterations.

Mr Hodges defended the council's decision not to include more detailed information for the second time in the letters because that information was available on the council's website and at open days.

However, councillors Dave Macpherson, Ewan Wilson and Angela O'Leary said the letters should have provided detailed information.

Councillors have labelled last week's problem "Floodgate" and are bracing themselves for what they have dubbed "Powergate".

Mr Macpherson said property owners in Silverdale, Ruakura, Fairview Downs and Rototuna - within which the 29km of lines fall - should have been told what corridor they were in.

"It's a similar version of Floodgate. People want exact information. They don't want generic information that worries them unnecessarily and we don't want that either."

Mr Wilson said: "The letters are again alarmist. In light of Floodgate and the fact we followed this up so quickly shows a systemic failure in our communication strategy and implementation."

Ms O'Leary questioned how many letters like these were being sent out and was concerned that many residents would be scared.

Meanwhile Hamilton Deputy Mayor Gordon Chesterman said the council urgently needed to tell owners the exact risk to their properties from flooding after last week's uproar.

"This whole episode has made the council look extremely unprofessional and regrettably the blame is falling on the political wing."

The letter failed to give residents details of what category - low, medium or high - their properties fell under, but said it would restrict development in some areas. Of the 28,000 at-risk properties, about 6000 are high risk.

The council said there was only a "small possibility" properties could be affected by floods, but it had a legal responsibly to tell people.

It planned to assess all 28,000 properties over the next four months and new letters would be sent to property owners telling them how at-risk their properties were.

Flood estimate
28,000 Hamilton property owners were told properties had a flood risk.

Only 6000 properties are high risk.

1 per cent chance of significant storm happening in any given year was in 1958.

From May 1, flood impact information will appear on LIM reports.

Power play450 Hamilton property owners will be told they could face restrictions depending on how close their properties are to the transmission corridors.

Some property owners could be prevented from doing any building work.

The information will not be on LIM reports until after the consultation process.

The specific rules on protecting the corridors could change.