The Sizewell C nuclear power plant in Suffolk is under review as the government looks to cut spending to fill the UK’s £50bn fiscal ‘black hole’, according to the BBC.
Sizewell C was expected to provide up to 7% of the UK's total electricity needs, but critics have argued it will be expensive and take years to build, the report said.
A government official told the BBC: “We are reviewing every major project - including Sizewell C.”
The BBC said another project under review was a new high-speed rail line in the north of England.
Former prime minister Liz Truss had pledged to build a major rail scheme in northern England in full, with a high-speed link eventually connecting Northern towns and cities from Hull to Liverpool, through Bradford.
But the plans for the rail line - known as Northern Powerhouse Rail - are now expected to be reduced.
"There wasn't really much point in going and blasting new tunnels through the Pennines… It's not true to say we're not delivering on what we said we would do on levelling up the north," the new business secretary Grant Shapps told the BBC.
Henri Murison, chief executive of the Northern Powerhouse Partnership lobby group, said scaling back the rail line raised "serious questions" about the government's plans to boost growth, according to the report.