A Labour MP has accused the Prince of Wales of being "less than frank with the country" over his marriage to Camilla Parker Bowles.
The Ascot Room in Windsor where Charles and Camilla will marry
His comments follow confirmation from the Department for Constitutional Affairs that she would become Queen when Charles succeeds to the throne.
Charles previously announced Camilla would be Princess Consort, not Queen.
But Thurrock MP Andrew McKinlay said new legislation would be needed to stop her having the rights of a Queen.
Constitutional Affairs Minister Christopher Leslie confirmed her future status when questioned in the Commons.
The Labour MP asked Mr Leslie if next month's marriage was "morganatic" - a term which would mean that Mrs Parker Bowles would automatically not inherit the title of queen.
Mr Leslie said that it was not a morganatic marriage.
Government sources have said that legislation would be needed to "comply with her wishes not to become queen".
Mr Mackinlay said legislation would be needed in 17 parliaments around the world, where the British monarch is head of state, for the change to be made.
Mr Mackinlay said such a legislation change "shouldn't be done for one man and one man alone".
He added that the Government may fear that asking parliaments in countries such as Canada, New Zealand and Australia for a change in legislation could stir up republican sentiments there.
Speaking on Radio 4 Mr Mackinlay said: "Prince Charles has been less than frank with the country - he knows that it was established in 1936 that the King's spouse automatically becomes Queen unless there is a law passed to the contrary."
Mr Mackinlay added: "I think he [Prince Charles] is deliberately holding this wedding under the smokescreen of a General Election."