Despite being a manifesto pledge, Theresa May's government u-turned on the idea of allowing new free schools more freedom on their admissions policies.
The current law means they're only allowed to select 50 per cent of pupils on grounds of faith.
Critics of the cap say faith schools have to decimate against pupils of their own faith.
For example, a Catholic school can't automatically select Catholic pupils once they've exceeded 50 per cent capacity - going against the Church's commitment to provide a Catholic school place for every Catholic child in their respective dioceses.
It means the Catholic Church has been hesitant to commit to opening new schools.
Calling on ministers to re-evaluate during a debate in the House of Commons, Conservative MP Sir Edward Leigh said: "Since the Government broke their manifesto pledge to allow the opening of Catholic free schools by removing the faith cap, the Catholic Education Service has had to find 50,000 new places.
"Despite a convoluted plan by the previous Secretary of State to open new voluntary-aided schools, not a single new Catholic voluntary-aided school has opened and only one is out for consultation. Now we have a new Secretary of State, will he bring some vim and vigour to this and try to fulfil our manifesto pledge?"
In his response, Education Secretary Gavin Williamson said: "I promise my right honorable friend that we will bring plenty of vim and vigour to this and I will be looking at it closely."
The Catholic Church has previously called on the government to reconsider the cap.