Nadhim Zahawi has insisted he was right to set out tax proposals in his bid to be prime minister after criticism from the Bank of England governor.
The new chancellor hit back at Andrew Bailey who carefully rebuked him for promising tax cuts in media interviews.
Bailey said there were some things that should only be said when the chancellor is announcing a budget.
But Zahawi told BBC Breakfast: “I’m setting out my stall as prime minister and I have fully costed these pledges, and I’ll be saying more about the way we’ll pay for that in the coming days.”
Bailey made his comments on Monday when he was quizzed by MPs over promises Zahawi made to cut income tax by 2p over the next two years.
He declined to answer several questions that touched on the election of the next Conservative party leader.
But Labour’s Angela Eagle repeatedly asked about Zahawi’s comments in interviews.
She said: “Normally financial policy and fiscal policy, which you have to take account of, is done in budgets, not in Tory leadership elections by an existing chancellor.
“I care less about what the other 15 or 20 or however many there are at the moment think about this, but I do care about somebody who is actually the chancellor who is running around doing it.
“That can move markets, can’t it? That can cause problems.”
In response, Bailey said: “I don’t like offering views on the constitution, but I don’t think things that should be done in budgets can ultimately be done outside budgets but, obviously, all of you have all sorts of views on these matters.”
Zahawi also made a thinly veiled swipe at his predecessor Rishi Sunak on Tuesday, saying that “cutting taxes isn’t a fairytale”.
He said in his leadership campaign video: “I believe cutting taxes isn’t a fairytale but rather a critical step to tackle the cost-of-living crisis.”
Sunak had accused his Tory leadership rivals of being dishonest and indulging in “fairytales” with their promises to cut the tax burden.
Zahawi is one of many candidates vying to cut taxes if they become the next prime minister.
Others, including attorney general Suella Braverman, foreign secretary Liz Truss and former foreign and health secretary Jeremy Hunt, have also promised to reduce taxes.