Therese Coffey has written to the minister in charge of giving Sizewell C the green light after being "surprised" by last week's decision.
The Suffolk Coastal MP said she expected a judicial review to be launched into Secretary of State for Business, Energy and Industrial Strategy Kwasi Kwarteng's decision to build the new nuclear power station in her constituency.
Dr Coffey said: "Last week the Secretary of State decided to grant permission for Sizewell C to be built with a significant number of conditions.
"Since then, I've spent time looking through the long report. The main question people understandably are asking is why the Secretary of State went against the recommendation of the Planning Inspectorate, which surprised me too.
"I have written to the Secretary of State to seek a meeting to discuss this further and how he intends to ensure the conditions of the order will be fulfilled.
"This is critical after other significant projects, including windfarms, managed to change their conditions without any particular public involvement.
"While there is no formal appeal process against the decision made by the Secretary of State under the 2008 Act, I expect that applications will go to the High Court for a judicial review of the process."
Among the key issues that were raised by the Planning Inspectorate was how fresh water would be delivered to the site.
Following the decision, Tom McGarry, head of regional external affairs & development for Sizewell C, insisted that the energy giant had plans in place to ensure there was enough water on site.
He said: "For the initial months of the early stages of construction water tankers will come to the site while the desalination plant is being built.
"Once the desalination plant has been built, that's how we will provide potable water on-site during construction.
"There will be a condition about the upper limit of heavy goods vehicles that we can have on the A12. Those tankers will not exceed that peak."
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