One Nation MP Barnaby Joyce has failed to guarantee the party will cost all of its policies ahead of the election after the Coalition claimed the rightwing party’s agenda would destroy the budget and drive up interest rates.

The opposition leader, Angus Taylor, last week used a major speech to argue Hanson’s platform would cost more than $1tn over a decade, force the Reserve Bank to lift rates and even risk a sovereign debt crisis.

Appearing on Sky News, Joyce – who is now One Nation’s treasury spokesperson – brushed off Taylor’s attack.

Sky News host Andrew Clennell asked Joyce if the party would submit all of its policies to the Parliamentary Budget Office (PBO) for costings, to which he replied:

We will do it to the best of our ability.

Pressed for a guarantee, Joyce said:

I’m not going to give a sort of guarantee like that, Andrew, because that means I have the resources to do it.

And if I get the promise that we’re going to have the resources to do it, it certainly makes it a lot easier.

It is important to note that One Nation’s staffing numbers should have no bearing on its capacity to submit costings to the PBO. The budget office is available to all MPs – including independents – to provide independent analysis of their proposals.

Asked by Clennell if One Nation would be prepared to fund additional staff itself, Joyce said:

We’ll have to.