EDF executives have been called back to parliament to explain why they have further delayed making an investment decision on a planned £18bn nuclear power station at Hinkley Point in Somerset.

MPs on the energy and climate change committee want to hear from EDF chiefs after the French economy minister, Emmanuel Macron, said the final decision could be delayed until September – four months later than expected.

Angus MacNeil, the chair of the committee, said: “When EDF appeared before us in March, company bosses were insisting that a decision would be made in May. At that hearing, we said that we would call them back in if that timetable slipped again and that’s what we are doing now.”

The committee said it expected the hearing to take place in late May.

“If Hinkley does not go ahead, it could have huge implications for our future energy security and efforts to cut climate-changing emissions. We will therefore be watching progress on this closely. If we have to see EDF back here in September as well, we will,” MacNeil said.

Macron told a French newspaper that various prerequisites would have to be met before EDF, which is 85% owned by the French government, could go ahead with building two reactors at Hinkley Point C.

An improvement in EDF’s financial position and consultation with French trade unions were among the conditions needing to be satisfied in order for the project to go ahead, he said. “The final investment decision could be confirmed next September,” Macron added.