Politicians on all sides of politics are guilty of rushing to announce large projects without sufficient planning, leading to "announcement remorse", says the head of the Productivity Commission.

Peter Harris, chairman of the independent government body, said federal and state governments were rushing in to announce big new investments without stopping to think about the benefits to the public, despite lessons learnt from major projects such as the National Broadband Network.

Victorian Premier Denis Napthine speaking with state Minister for Transport Terry Mulder and federal assistant minister for Infrastructure and Regional Development Jamie Briggs. Credit:Justin McManus

"The sad thing is, regardless of who is in government, the same rush to announce still seems to be with us," he told an infrastructure conference in Melbourne.

"The sequence of announcing the project concept, then doing the planning – after which the concept is almost always revised – and with the cost-benefit analysis either not done at all – for lack of time – or not released – generally on the unconvincing grounds of commercial sensitivity – is unfortunate."