Doubts have emerged about how quickly Labour and National could implement their plans to bring forward infrastructure investment to boost economic growth.
Both parties say their proposals to rush spending on roads and other infrastructure will put money into the economy and help keep people in jobs during the recession.
However Radio New Zealand's political editor says it is unclear how much work could start on new infrastructure next year, when it is likely to be most needed.
National Party leader John Key says his party would complete the Waikato Expressway within 10 years, but he has confirmed that the work would not start anytime soon.
Labour leader Helen Clark says a Labour-led Government could start some new capital works next year, but she is not prepared to give details.
Labour promises that if it is re-elected it would produce a mini-Budget in December, and will not release details until then.