The cross-Channel interconnector is due to come ashore at Eastney if approval is given by business secretary Kwasi Kwarteng.
Ms Mordaunt said: ‘Beis can be in no doubt of the strength of feeling against Aquind and the arguments against this proceeding - it would make us as a nation less resilient, stifle local economic recovery and damage the environment.’
A decision is due by September, with a recommendation already with civil servants.
Aquind director Richard Glasspool told Sky News: ‘We don't see any link between making political contributions to the Conservative Party and what we're doing as a project.
‘Absolutely not. Aquind as a project since its inception, and through where we are now, received no favours from any party. It has been an uphill struggle all the way.’
Labour previously said it would be a ‘total fantasy’ to think the political decision on the plan would be impartial.
Aquind refused an interview request from The News.
The company previously said its plan will ‘keep the lights on’ for 5m British households, and is an ‘essential part of the national infrastructure’ to meet climate change targets.
It will save consumers between £2bn and £3.8bn and cut CO2 emissions.
A spokesman said: ‘The project will create and support hundred local jobs during the construction stage, and has been carefully designed to avoid and minimise impact on the environment and local communities.’