Foreign Secretary James Cleverly said the Government is focused on getting economic growth despite the market turbulence.
Allies of Liz Truss have rallied round the Prime Minister after she came under intense pressure from her own MPs to abandon her economic plan following a market backlash to the measures.
The Tory leader endured a bruising appearance with her backbenchers on Wednesday evening but her supporters insisted her tax-cutting, pro-growth agenda must be allowed to progress.
With Ms Truss’s leadership already being questioned after little more than a month in the job, Foreign Secretary James Cleverly said a change at the top of the party would be a “disastrously bad idea”.
At a stormy meeting of the backbench 1922 Committee in Westminster on Wednesday, Commons Education Committee chairman Robert Halfon told Ms Truss she had “trashed the last 10 years of workers’ Conservatism”.
Meanwhile, the editor of the influential ConservativeHome website, Paul Goodman, suggested there has been speculation about replacing Ms Truss with a joint ticket involving her former leadership rivals Rishi Sunak and Penny Mordaunt.
But Mr Cleverly told BBC Radio 4’s Today programme: “We have got to recognise that we do need to bring certainty to the markets.
“I think changing the leadership would be a disastrously bad idea politically and also economically.
“We are absolutely going to stay focused on growing the economy.”
Chancellor Kwasi Kwarteng, who is in Washington for the International Monetary Fund’s annual meeting, has already been forced to abandon plans to scrap the 45p income tax rate for top earners.
Mr Cleverly declined to rule out further U-turns but insisted the Government will “absolutely stick” with its tax-cutting principles.
The Chancellor is now under pressure to reinstate a planned increase in corporation tax from April in an effort to reassure the bond market that the Government does have a strategy to get the public finances under control.
But Mr Cleverly told Sky News: “I think that it is absolutely right that we want to invest in businesses. It is absolutely right that we help them stay competitive, we help them stay afloat.
“We have got to make sure we can compete internationally with the other places businesses can choose to locate. We have got to make sure we are tax-competitive.”
Asked if the Government will stick with the policies of the mini-budget, he said the “bulk” of the mini-budget was the package to protect households and businesses from soaring energy costs.
But it was also “about making sure that taxes for 30 million people were reduced a little bit and those are really strong principles” and “I think we should absolutely stick with those”.
He said the planned statement by the Chancellor on October 31 will set out a more “holistic” view of the Government’s plans, but the “foundations” of the mini-budget were “really key for the growth agenda the Prime Minister has put forward”.
Veteran Tory backbencher Sir Christopher Chope insisted he has “absolute confidence” in the Prime Minister, telling Times Radio: “If I was a betting man I would now be going out and putting money on the Conservatives winning the next general election, not with a landslide but certainly with a good majority.”
The Government’s plans revolve around securing an increase in economic growth – with a target of an annual rise of around 2.5% in gross domestic product (GDP).
The forecasts presented by the Office for Budget Responsibility (OBR) alongside the Chancellor’s October 31 statement will give an assessment on whether that is viewed as a realistic ambition.
But Business Secretary Jacob Rees-Mogg has suggested the Government could ignore OBR forecasts accompanying the strategy if they predict low growth and rising debt.
He has also blamed the Bank of England for the turmoil in the value of sterling and the rising cost of Government borrowing, while former Tory leader Sir Iain Duncan Smith said Governor Andrew Bailey’s handling of the situation had been “stupid”.
Mr Cleverly said “of course he is not stupid” but “it doesn’t mean we always agree with everything the Bank of England Governor says or does”.