Cameron said after meeting Sarkozy in Paris that the crisis was having a chilling effect on the British economy, and called for a successful outcome to a summit next week when the Franco-German plans will be put to European Union leaders.
Britain wanted to help solve the crisis, he told reporters, but repeated his line that if treaty renegotiation turned out to be needed, any changes would have to be in Britain's interests.
Under pressure from eurosceptic members of his Conservative party, Cameron has signaled he may try to use any treaty re-negotiation as an opportunity to wrest back some powers from Brussels to London.
However, he has said that the priority is to resolve the crisis, saying it would give a bigger boost to the struggling British economy that any other move.
Cameron said the euro zone needed its institutions to "get behind the currency" to convince markets it had the required firepower and that there was real competitiveness so the bloc worked properly.
"Neither of those things require treaty change, but if there is treaty change I will make sure that we further protect and enhance Britain's interests," he said before boarding a train back to London.
Sarkozy, who laid out his vision Thursday in a speech for redrawing Europe's founding treaty to create more central control over national budgets, sought to allay concerns by Cameron that a rejig of EU governance could reduce British influence.
"We discussed the crisis in the euro zone which is having a chilling effect on the British economy and the need for a successful outcome to the European summit next week," Cameron said after meeting Sarkozy for just over an hour.
Sarkozy and German Chancellor Angela Merkel are pushing to give Brussels more power to enforce fiscal discipline in euro zone states, ideally through treaty changes that will be put to the make-or-break summit on December 9. The bloc faces a week of intense diplomacy between now and then.
Sarkozy and Cameron cooperated during their joint leadership in the Libyan crisis but in October they argued bitterly for more than an hour over the best way of combating the crisis, diplomats present during the discussion said.
Sarkozy, who faces a bruising fight to stay in power in an April election, is under pressure from rating agencies concerned the deepening euro zone crisis is putting France's top-notch AAA credit rating under strain.
He and Cameron also discussed Iran after protesters stormed Britain's embassy in Tehran this week, causing London to close its diplomatic mission there and expel all Iranian diplomats from Britain. France recalled its ambassador for consultations.
"It was an opportunity to thank President Sarkozy for the help the French gave to our staff and our embassy (and) turning up the pressure on Iran with further sanctions," Cameron said.
European countries, led by France and Britain, have indicated they are considering imposing an oil embargo on the world's fifth-biggest oil exporter.
The two leaders also discussed the need to put "massive pressure" on Syria, as Cameron put it, over the crackdown by President Bashar al-Assad's government on the civilian population.