The cost of upgrading the Lucas Pl roundabout and Sir Henry Wigley Dr, in Frankton, has ballooned by $247,000 to $696,925 because more pavement and stormwater improvements are needed than budgeted for.
The Queenstown Lakes District Council's utilities committee yesterday approved the concept design for the project.
Lucas Pl roundabout and Sir Henry Wigley Dr provide the main access into the Queenstown International Airport and connection to State Highway 6.
Council infrastructure services manager Mark Kunath said the budget was set at $436,000 in April and moved to the concept-design phase in August.
The concept design showed the actual cost would be $696,925.
"Pavement testing and further stormwater investigations resulted in a significant increase in the estimated project costs," he said.
The pavement on Sir Henry Wigley Dr was in "poor structural condition and inadequate", he said.
The extent of the stormwater system required for the area was greater than identified in the scoping report.
He said the New Zealand Transport Agency would subsidise the project by $324,000.
Cr Vanessa Van Uden said the Queenstown Airport Corporation should pay for some of the upgrade.
"I don't think there's any justification for the airport not to contribute their share."
The committee members adopted a motion for council staff to discuss shared costs with the corporation.
