"Fiscal policy should be aligned with monetary policy," Gourinchas said at a news conference in Washington, when asked about Britain's economic situation and the turmoil in its government bond market.
"Central banks are trying to tighten monetary policy, and if you have at the same time fiscal authorities that try to stimulate aggregate demand, it's like having a car with two people in the front ... each trying to steer the car in a different direction.
"Now what we've seen in the UK market, we've seen market dysfunction, related to some illiquidity in some segments," Gourinchas said.
The IMF published new growth forecasts for Britain on Tuesday, although these were finalised before Kwarteng's Sept. 23 statement.
The Fund expects British economic growth to slow to 0.3% next year compared with a July forecast of 0.5% growth for 2023.