Labour Party leader Phil Goff is attacking the National Party's fiscal credibility, saying its figures are shonky.
National leader John Key used the same word to deride Labour's election costings almost a week ago.
National has promised to give $400 million to irrigation schemes if it is re-elected.
The money would come from the profits factored in from partial state asset sales.
Schools would get $1 billion and hospitals and roads would also benefit.
Mr Goff says the figures are shonky and overlap between projects.
Labour's finance spokesperson David Cunliffe says the figures are more marketing than substance.
Mr Cunliffe says National is deliberately keeping its numbers vague but the situation is becoming a joke.
Green Party co-leader Russel Norman agrees there is not enough precision in National's promises.
Dr Norman describe's National's numbers as rubbery and says it is hard to know if its spending list is realistic.
ACT leader Don Brash says even if the prices expected for the assets National plans to sell fall short, extra borrowing to bridge the gap would be appropriate.