Conservative Party Chairman Grant Shapps said the issue of relations with the EU "should worry the country", but that the Tory's pro-Europe coalition partners made it impossible to act before 2015.
"We are in a coalition and that coalition runs to 2015", he told the BBC's Sunday Politics.
I do want to see powers repatriated from Europe.
We've said that is going to be our objective, and one of the pitches [at the next General Election] will be to people in all kinds of seats around the country that if we want to have this reformed relationship where we are in Europe but not run by Europe then we do need a majority Government.
Europe and all that stuff should worry everyone. And it should worry the country because our relationship, and getting that relationship right with Europe, is critically important.
More top news
An international manhunt has been launched for a husband and wife wanted in connection with an attempted murder.
The owner of a dog who was rescued from England's highest mountain is being sought by an animal welfare charity.
A vicar who was diagnosed with HIV after being attacked two years ago has created a powerful video to share her story with her congregation.