Asked by a reporter if Sunak's comment meant that fracking was "back in the [dust] bin", Sunak's spokesman said "That's correct."
"You've got the position set out in the manifesto, which the prime minister pointed to," the spokesman told reporters. "Obviously it'll be for BEIS (the Business, Energy and Industrial Strategy department) to come forward with a bit more detail on that.
Sunak said he stood by a 2019 Tory manifesto commitment on the issue, which said they would "not support fracking unless the science shows categorically that it can be done safely."
During her short term as prime minister, Liz Truss had lifted a moratorium on fracking, arguing last month that strengthening the country's energy supply was a priority.
Truss had said fracking - extracting shale gas from rocks by breaking them up - would be allowed where it was supported by communities, but the plans had faced opposition from many lawmakers, including from her governing Conservatives.
Fracking has also been opposed by environmental groups and some local communities. It was banned in 2019 after the industry regulator said it was not possible to predict the magnitude of earthquakes it might trigger.