Hundreds of homes are in the firing line of a new arterial road for South Auckland - of which the first section alone is costed at almost $250 million.
Auckland Transport says about 260 properties, many of them along Redoubt Rd above Manukau, are in the path of the first stage of what it ultimately envisages as a 32km eastern bypass of the Southern Motorway to Drury.
The council organisation revealed last night a cost estimate of $246 million for the 9.2km section from Manukau and Flat Bush to Alfriston east of Manurewa, parallel with Mill Rd - including $66 million for property purchases - although it has yet to hazard a price for the full project.
Only $82 million is allocated for the next 10 years, and the project could take twice that time to complete.
But it intends seeking a route designation for the first section from the council's planners by the end of next month, and says it is powerless to stop landowners from building new homes until then.
The plan has horrified residents of the historic Redoubt Ridge, through which Auckland Transport intends carving a road corridor up to 30m wide, past a remodelled junction with a widened Murphys Rd running from Flat Bush.
Redoubt Rd resident Raewyn Roberts, spokeswoman for an action committee to fight the proposal, yesterday called on Auckland Transport to avoid destroying what remained of a valuable ecological corridor from Murphys Bush to Totara Park and beyond.
She said it should instead press the Government's Transport Agency to widen the Southern Motorway and alleviate a serious bottleneck caused by what she called a poorly-designed new connection with the Southwestern Motorway.
Long delays on the motorway were prompting many drivers to turn off at Manukau and head up Redoubt Rd, causing safety concerns which she accused Auckland Transport of exploiting to strengthen its case for a bypass.
Meetings held by Auckland Transport had reduced some of her neighbours - including migrants who had recently moved on to the road - to tears.
"It's appalling," she said. "This is a mega, mega project - they have this massive dual carriageway which will come roaring up from the old Manukau City centre, wipe out the ridge, then sweep down Mill Rd."
A distraught fellow committee member, Eve Osborne, said she and her husband were assured by officials before buying their large colonial-style home further up the ridge for "close to $1 million" in 2011 that the road would avoid the property.
They moved in after being built out by neighbours in Glendowie, but had to halt badly-needed renovations to the Redoubt Rd property in October after learning the road would be "going smack through this house" and those on either side.
Auckland Transport spokesman Mark Hannan said the road had been flagged as a strategic arterial route in the 30-year Auckland Plan, and was a priority project needed to cope with future growth from Flat Bush to Drury.
Although its preferred alignment "shows an impact" on about 260 properties, among more than 400 along the first stage of the road corridor, he said many may be affected in only minor ways.
* Redoubt Rd-Mill Rd-Murphy Rd corridor:
* 32km long to Drury.
* $246 million for the first 9.2km stage, cost unknown south of Alfriston.
* About 260 properties affected in first stage.
* Likely to be built in several stages over 20 years.