Wellington City Council is to cut the amount it spends on renewing its infrastructure.

As part of its long term plan, the council has decided to reduce the spend by $100 million over 10 years.

Councillor Iona Pannett says this affects stormwater, wastewater, drinking water and roading.

She says this is the first time this approach has been taken in New Zealand.

"And my concern is that if the approach is wrong that essentially we've left ourselves short of a lot of money."

Pannett says the decision's been made after detailed assessment of Wellington's pipes and roads.