National won't yet say if it plans to support legislation to create an independent body to cost political parties' policies before an election.
The Government announced it would create an Independent Fiscal Institution (IFI) in last year's budget.
A recently released Treasury discussion document revealed the Government intended to develop a bill to be introduced to Parliament this year.
Asked when the bill would be introduced, a spokesman for Finance Minister Grant Robertson said: "These are matters that are under consideration as part of the Budget process, so we can't comment".
The establishment of the IFI would require changes to the Public Finance Act.
But National finance spokeswoman Amy Adams would not commit to the party supporting changes to the legislation, as there was too little detail and too many unanswered questions to be able to form a view at this stage.
But she said she was "a little sceptical" about what the Government was trying to achieve by establishing an IFI.
"While I remain open-minded at this stage, the more we go into it, the more we realise there are a lot of unanswered questions.
"Until the Government can fill in some of those blanks, it's impossible for us to reach a view."
The role of the IFI would be to independently cost political party policies to make sure they could feasibly be paid for.
"Recent elections have seen a significant focus on fiscal policy and the cost of election platforms," the Treasury document said.
A notable example of this was last election's $11.7 billion "fiscal hole" saga, whereby National claimed Labour's policy numbers did not add up.
Labour refuted this and spent weeks explaining its policy costings.
The Treasury document said providing consistent costings to all parties would enable a higher level of public scrutiny and improve the debate of election promises.
Many other countries already have such a body – of the 36 OECD countries, 27 have either a fiscal council or a parliamentary budget office which scrutinises party policies.
Australia, for example, has the Australian Parliamentary Budget Office which was established in 2012.
The creation of a New Zealand IFI was recommended by the OECD in 2017.
Although the Government was yet to form a view about who would be on the IFI, or how the appointment process would work, the Treasury has a number of suggestions as to how an IFI would be overseen.
For example, it could be part of the Treasury or it could be a completely new department and set up as a statutory crown entity, much like a DHB.
The Treasury also said it could come under the purview of the Auditor-General or could become a new legislative branch department.
At the moment, political parties are able to request Government departments, like the Treasury, to cost their policies as long as they have the Finance Minister's approval.
But over the last eight general elections, the Minister of Finance has stated that the Government would not request the public service to cost political parties' policies.
Instead, Opposition parties have had their policies costed by independent economic firms – in 2017, Labour had its numbers scrutinised by BERL.
The Treasury asked for submissions on how the Government would implement an IFI.
Neither National nor Labour provided a submission.