In an interview with the French weekly newspaper Le Journal du Dimanche, Macron said French President Francois Hollande "has confirmed France's engagement" in the project, and that "the final decision on investment could be confirmed in September".
That final decision had been expected in May, but EDF, which is 85 per cent owned by the French state, announced a delay on Friday saying it first had to consult with an internal committee as demanded by French unions. Such consultations risk setting the project back by several months.
On Sunday, Macron said the investment in the two reactors at Hinkley Point would be equivalent to a year of investments by EDF. "This won't shake its financial trajectory," said Macron, denying rumours France could pull out of the project.
Macron added that the project would promote French technology in the face of American, Chinese and Russian competition.
Hinkley Point, which EDF is to build in partnership with China General Nuclear Power Corporation (CGN), will be Britain's first nuclear power plant in decades and is to provide seven per cent of its energy needs by 2025.
With a projected cost of 23 billion euros, it will also be one of the world's most expensive nuclear power plants. Questions have been raised about the financial viability of the project as EDF is struggling with a debt pile of more than 37 billion euros. On Friday, the French government announced that it would inject three billion euros into the energy provider, as part of a four-billion-euro capital increase.