They're suburbs within suburbs and they're popping up all over Auckland.

Building consents may be down overall, but large-scale residential developments are on the cards with thousands of homes planned for construction at Orewa, Long Bay, Mt Wellington, Karaka, Takanini and Hobsonville.

Experts are split over the merits of the developments, with up to 3000 new homes promised in some areas. They're either a solution to growing demand or a potential eyesore.

Work is at varying stages on plans at Auckland Council for major developments at Hobsonville Pt (3000 homes); Stonefields, Mt Wellington (2500 homes); Millwater, Orewa (3000 homes); Long Bay (2500 homes); Karaka Lakes (400 homes); Karaka Harbourside (442 homes); Addison, Takanini (1500 homes) and Kensington Park, Orewa (690 homes).

However, property investor and financial advisor Olly Newland said the homes looked "nice and pretty" when first built but questioned whether they would end up as slums.

"What will they look like in 20 years? Will they have character or soul? They'll all look the same - like Japanese cars. We want character but cheapest always wins."

Newland said there were plenty of state houses on large lumps of land in Glen Innes and Panmure - "it's close to infrastructure and close to town and you could double the numbers living there quite comfortably".

But the dean of the University of Auckland's School of Architecture, Professor Jenny Dixon, said the projects were an answer to the city's housing crisis and would go some way to meeting the demand for the 170,000 new dwellings the city would require by 2026.

"They're a response to Auckland's growth strategy and a need for urban intensification. We've made a longstanding commitment to intensify the isthmus and keep metro urban limits ... we have to construct a large number of houses over the next 20 years to meet the needs of the city's population."

New developments would succeed so long as they were of quality. Everything depended on developers, Dixon said. "It has to make financial sense for them as well."

Auckland Council chief planner Roger Blakeley said Auckland's exploding population was one of the issues up for discussion in the Auckland Draft Plan, which plans what the city will look like for the next 30 years.

"The challenge is to make sure the quality of our building environment matches the beauty of our natural environment," he said. Newland said if we weren't careful we'd end up with "little ticky tacky houses all the way from Hamilton to Whangarei".