State Treasury has completed Liberal party election castings, estimating debt will be down in 2019-20.

Treasury predicts debt will be down from $28.8 billion down from the forecast $41.1 billion.

The Government says the reduction in debt will be due to the partial sale of Western Power.

State Treasurer Mike Nahan there will be two thousand voluntary redundancies in the public sector, and around half of those redundancies will be for people over 55.

He spoke with Oliver Peterson.