Wellington's mayor is satisfied with the levels of investment into the city's under-fire water infrastructure

There have been two major wastewater pipe failures in recent weeks, with contractors scrambling to fix problems in the CBD and at the Moa Point treatment plant.

Andy Foster says the failures can't be put down to under-investment.

He says they spend about 180-million dollars a year, but this will be rising over a period of time when more pipes start to age.