No excuse for costing delays: PBO

Political parties should release their election promise costings with enough time for voters to digest them, says an independent agency.

The independent budget watchdog says it's reasonable for voters to expect policy costings to be released well before election day.

The Parliamentary Budget Office's annual report, tabled in parliament on Wednesday, said it had responded to 3251 requests for policy costings and budget analyses in 2015/16 - more than double that of the previous year - with an average response time of 18 days.

"It is reasonable for the voting public to expect the costed election platforms of the major parties to be released prior to polling day in sufficient time to be taken into account in their voting intentions," the report said.