The cost to complete the first stage of the Kamo Shared Path has increased by a third.
The contract for the Rust Ave to Cross St stage was originally awarded for $1,872,317.91 but an item at the infrastructure committee meeting on Thursday asked the councillors to approve an additional $629,130.55, taking the total cost to $2,501,448.46.
Whangarei District Council roading manager Jeff Devine said some of the increase issues were out of their control and some relate to the boundary of the properties the path goes past.
A breakdown of the extra costs shows an additional $121,902 was needed to extend the project along Rust Ave from the rail overbridge to the location of a future pedestrian crossing, and $33,819 was needed for unanticipated gum tree removal and restoration.
There was $237,872 spent on changing the boardwalk from a timber deck to concrete beams to allow rock-fall protection to meet the consent conditions and installing a non-climbable fence along the facade of Whangarei Club to meet easement conditions.
"One of the concerns was the rocks on the [KiwiRail] embankment could dislodge. We had to adapt to meet the concern for public safety."
Another $13,153 was spent modifying the disability access near the University of Auckland campus to meet easement conditions and $132,384.55 was spent on making changes according to KiwiRail safety audits during construction.
The remaining $90,000 is contingency.
Mr Devine said this was the first of the "more complicated" shared paths being built.
"We have learned some of the lessons. Some of those lessons will be taken forward to the other stages."
He said they will make allowances for risks in the planning stage of the next ones.
Mayor Sheryl Mai asked for there to be no more surprises in the next stages.
Councillor Vince Cocurullo said although the figure is "quite significantly" more than he would like, KiwiRail is "one of the hardest" organisations to deal with because it constantly changes the rules.
The Kamo Shared Path is being built in four stages. The total allocated budget is $8.575 million, which includes $2m of minor improvement funding for intersection and rail crossing updates which will be completed as part of the project.
The funding for the extra works will come from existing budgets.