Wellington City Council may need to slash tens of millions of dollars off its budget.

City Councillor Diane Calvert says they've had a behind closed doors meeting on the state of the council's finances.

She sought legal advice to reveal the financial details and says capital expenditure needs to be cut by tens, if not hundreds of millions of dollars, in the coming years.

She says these financial problems were a long time in the making.

"We really had a spending program that we couldn't afford, because it was clear even two years ago that economic conditions were going to change."

LISTEN ABOVE