A huge community-led effort to find missing Alexandra woman Denise Potter has prompted a police warning to the public that the search needs to be co-ordinated.
Mrs Potter has been missing since Monday.
She was last seen at her daughter's home in Carroll St, Dunedin, about noon.
Inspector Jason Guthrie, at a media conference yesterday, reminded searchers not to enter private property.
He said information such as possible sightings should be given to police directly, by phoning, or posting directly to the police Facebook page.
He said people were posting material on different Facebook pages, which meant police could miss important information.
Insp Guthrie urged residents in the Carroll St, Mornington, and Town Belt area to check their properties.
A sighting was crucial for the investigation to move forward.
The disappearance was out of character, but police did not suspect foul play.
Husband Steve Potter, who spoke beside daughter Sharelle at the press conference, said he was humbled by the public's willingness to help.
Asked how he was coping, Mr Potter said the family was so busy searching they had not had time to grasp the seriousness of the situation.
''We have to keep going, but it does get to a point where we've actually got to start to look at the reality of the situation, but that's hopefully a wee way down the track for us.
''We just need to keep going until we find her.''
The lack of any leads after the extensive search was hugely frustrating.
He said his wife had been ''quite tired'', and he did not think she would have gone far.
Mr and Mrs Potter were in the public eye last year, after campaigning for more than eight years on behalf of Shane Cribb.
In a report last year, the Independent Police Conduct Authority agreed with the Potters that the police mishandled an investigation of a 2005 car crash between Mr Cribb's vehicle and an unmarked police ute driven by Senior Constable Neil Ford.
After the crash, Mr Cribb was convicted of causing injury by carelessly using a motor vehicle, but that was overturned after a rehearing.
Asked yesterday how it felt dealing with the police, Mr Potter emphasised his support for them, saying they did a fantastic job.
Every organisation had rogue elements, he said.
A search was also being carried out in Alexandra, in case his wife had tried to return home, Mr Potter said.
About 100 volunteers combed the St Kilda sand dunes yesterday in the search.
Local residents Marj Andrews, Andrea Macaulay and Tania Macaulay saw the missing person page on Facebook and decided to lend a hand.
They had no search experience but said it was important to ''do for others what they would expect others to do for them'' in a similar situation.
More than 5500 people have visited the missing person Facebook page and many have notified the family of areas they have searched.
Search co-ordinator and a family spokesman Manu Panirau said ''hundreds'' of people in the community had been involved in small-scale search efforts, which was ''great to see''.
''We've searched areas of interest thoroughly.
''Now we're getting out the map and organising wider searches.''
A police spokesman said there had been no official police search and rescue party out yesterday but police had previously searched ''areas of interest'' in Dunedin and Alexandra, where Mrs Potter came from.
Mrs Potter had been in Dunedin for about a week before she went missing.
Anyone with information should contact the police on 471-4800.
Mrs Potter was last seen wearing blue denim jeans, a two-toned black and grey long-sleeved, three-quarter buttoned shirt, and no footwear.
