Detective Sergeant Nik Leigh said today Mr Lowe could be anywhere in the lower South Island and appealed for sightings of him or his black BMW hatchback -registration number: HHR892.
"I'm doing some inquiries with BMW at the moment to see how far a tank of gas could get you," he said.
"I'm waiting to hear back from them and then we can get . . . a bit of a radius on where he might be.
"It's still a massive search area.
"It's a bit of a needle in a haystack."
He called on the public to report any potential sightings to police immediately.
Det Sgt Leigh yesterday said police had "grave concerns for his wellbeing" after he had been missing for three days.
Liz Carroll-Lowe said her husband’s disappearance had come as a "total shock", as the pair had just returned from a 13-day holiday in Te Anau.
"It was the best holiday in our lives. He only got back to work on Thursday. And this happened on the Friday."
Earlier this year, Mr Lowe had a workplace accident and spent several months off work.
Mrs Carroll-Lowe then suffered a serious illness and was in hospital for two months.
The vacation was to celebrate putting those difficulties behind them and next month would mark 20 years since the pair first met.
Mr Lowe left his Portsmouth Dr workplace in his black 2005 BMW hatchback about 10am. He told his boss he was "popping out for two minutes" and never returned, she said.
Her husband had suffered from depression in the past but had learnt to manage his anxiety and had been well for years.
The car had $50 of petrol in the tank and Mr Lowe had not used his bank cards or mobile phone since going missing.
"After three days, we are pretty worried. It’s possible we are only going to find a body, but we just want him home."
The support from the public had been "amazing"; people were helping to search and sharing his photo across social media. One man had even used his plane to search the area around Lake Mahinerangi.
"He’s a dad. He’s a husband. He’s a grandad. He’s a brother. And we just want to get him home."
• Dunedin police (03) 471-4800, Crimestoppers 0800 555 111.
