The £20 million building in Luton, is one of just ten centres in the UK to explicitly bring together PG and CPD study in a university setting.
Mr Willetts, who unveiled a plaque to mark the opening, said it was a sign that the university was "thriving and growing".
He added: "There are very few universities in the country that have the initiative to link up post graduate study and continuing professional development in this way. It makes a lot of sense.
"It’s a great opportunity and typical of the flair and flexibility of this university."
Praising the university’s "confidence and vision to invest in its postgraduate provision", Mr Willetts told guests: "Postgraduate study is becoming more and more significant. It has become the new frontier in social mobility.
"It brings together higher education and local businesses. This strengthens further the very strong links that I know the university already has with businesses."
Vice Chancellor Bill Rammell, who was Minister of State for Higher Education in the previous government, said: "Universities deliver only 5% of the UK’s CPD provision. We want to change that.This magnificent building, which was built on time and under budget, will be the focus for that."
He also spoke of the university’s excellent record for widening access which, he said, had seen Luton enter the top 5 areas in the country for the number of students entering higher education.