The IMF has launched a biting attack on the UK’s plan to implement £45bn of debt-funded tax cuts, urging the government to “re-evaluate” the plan and warning the “untargeted” packaged threatens to stoke soaring inflation.

The multilateral lender said it was “closely monitoring” developments in the UK and was “engaged with the authorities” after chancellor Kwasi Kwarteng unveiled the tax cuts last week, sparking a collapse in the value of sterling and a spike in the country’s borrowing costs.

“Given elevated inflation pressures in many countries, including the UK, we do not recommend large and untargeted fiscal packages at this juncture,” the IMF said in a statement. “It is important that fiscal policy does not work at cross purposes to monetary policy.”

The pointed criticism of Kwarteng’s fiscal plan came as some business leaders in the UK hit out at the tax cuts while the Bank of England’s chief economist warned it would need to react with a “significant monetary response”.

The IMF said it understood the UK government’s desire to help “families and businesses deal with the energy [price] shock” while “boosting growth” with tax cuts and supply-side reforms.

But it raised the concerns that the tax cuts, which will disproportionately benefit high earners, “will likely increase inequality”. It called on Kwarteng to use the budget on November 23 to “provide support that is more targeted and re-evaluate the tax measures”.

The unusually forceful intervention from the IMF came as the UK faced growing international criticism for its new economic plan, especially from the US. Ray Dalio, the billionaire founder of hedge fund Bridgewater, on Tuesday said the UK government was “operating like the government of an emerging country”.

Dalio’s remarks came after Larry Summers, the former US Treasury secretary, on Monday called the policy “utterly irresponsible” and said the violent market reaction was “a hallmark of situations where credibility has been lost”.

The pair joined Raphael Bostic — president of the Atlanta branch of the Federal Reserve — who this week warned the UK’s plan increased economic uncertainty and raised the odds of a global recession.

Last week, Jason Furman, a former economic adviser to Barack Obama, tweeted: “I can’t remember a more uniformly negative reaction to any policy announcement by both economists and financial markets than the UK’s policy”.