National leader Judith Collins needs to "show some leadership" and tell Paul Goldsmith to "rip up his budget", Labour's finance spokesperson Grant Robertson says.
Goldsmith has been dogged by multiple mistakes in his fiscal plan, leading to tough questions over if his party can be trusted to manage the economy.
In the latest reports, National and the economic fact-checkers it used have given different versions of the alternative budget, each with different figures.
Robertson has twisted the knife on Saturday with a statement calling on Collins to "stop avoiding the questions about her finance spokesperson".
"Paul Goldsmith and the independent agency National used to verify his numbers are now saying two different things about where the money is coming from, while another mistake was revealed yesterday," he says.
"Paul Goldsmith is now making mistakes about the mistakes he's made in his budget. These errors are ruining National's credibility. It's a shambles, and Judith Collings needs to sort it out. She needs to tell Paul Goldsmith to rip up his budget and start again."
Last Sunday it was revealed National used figures from May's Budget instead of the updated Pre-Election Fiscal Update (PREFU) in calculating how much it would save from halting NZ Super Fund contributions, which resulted in a $4 billion fiscal hole.
Collins dismissed this as "entirely inconsequential", adding the mistake "means very little" as the calculations were spread over 10 years.
National made the same mistake with its capital allowance - the money put aside to build things like schools and hospitals. This left National with another shortfall of $88 million.
And on Friday Goldsmith admitted he did not account for the loss of tax paid by the Super Fund - and despite that being worth near-on $2 billion, he insisted there's no hole.
"Our plan has been independently costed and it all stacks up."
Goldsmith's leader Judith Collins still thinks he has a future.
"Oh yes," she said when asked about him. "The fact is there is one number - so what?"
Robertson says New Zealand "cannot afford National and their mistake-riddled budget".
"It is not good enough for Judith Collins to call Paul Goldsmith's multi-billion dollar mistakes 'inconsequential' and play down the missing money," he says in his statement.
"It's time for her to stop avoiding the questions about her finance spokesperson and give some serious answers."
