David Cameron urges 'tactical patience' over eurozone integration
David Cameron has urged "tactical and strategic patience" over plans by eurozone economies to set up a closer financial union, instead of rushing to a referendum on the issue.
The prime minister has faced calls for a public vote on whether the UK should leave the European Union.
But the eurozone changes would not necessarily involve a "fundamental change" for the UK, he told MPs.
He said "difficult decisions" remained for the countries concerned.
Eurosceptic Conservative MPs are pressing Mr Cameron to hold a referendum on whether the UK remains in the EU, arguing that the developments in the eurozone, which is suffering a debt crisis, is creating a "two-tier Europe".'Sovereignty'
But the PM told the Commons Liaison Committee: "If the 17 countries of the eurozone bring about a banking union for themselves - which I frankly think they need to do in a single currency - if they do that at the level of the 17 and we can get proper safeguards in place, then that wouldn't be a fundamental change for us.
"So I don't think that would in and of itself trigger a massive change for us in the EU."
He said: "These countries are going to have to make very difficult decisions about giving up areas of sovereignty and restricting areas of their democracy.
"They are going to have more controls on what they can spend and what they can tax. That's a decision for them; it's not a decision for us."
On Monday, Mr Cameron told the House of Commons he did not want an immediate in/out referendum but said the "status quo" was unacceptable.
But "it would also be wrong to rule out any type of referendum for the future", he added.
Also on Monday, former Defence Secretary Liam Fox called for the nature of the UK's EU membership to be renegotiated - with a referendum to then follow on what was agreed.
He argued that Westminster powers were "being curtailed by diktat from Brussels" and that the situation needed to be addressed.
Asked during his Liaison Committee appearance whether a convention should be created to discuss the future of the EU, Mr Cameron said: "Clearly what is going to happen is if the eurozone is going to survive it will have to make moves towards a more integrated state. We won't be part of that."
He added: "I think we are only at the beginning of those conversations... there's a lot of work to be done. There's a lot of thinking to be done and a lot of conversations to be had before we get to any convention."