In an interview to appear in Sunday's Bild am Sonntag newspaper, Trichet said that he was, however, confident that euro zone governments would be able to restore financial stability provided the bloc's Stability Pact rules are comprehensively and more aggressively enforced.
Trichet said the agreements reached by European Union leaders this week need to be enacted in a very precise and quick manner. He called it "absolutely decisive" that those decisions are quickly and completely enacted.
He said the ECB will carefully track the progress of governments' reform measures and said the time had now come to "see some action."
"The crisis isn't over," Trichet told the German newspaper, according to an advance text released early on Saturday.
"But after the decisions made this week, I'm nevertheless confident that the governments will succeed in restoring financial stability," said Trichet in one of the final interviews of his term leading the ECB.
He said the precondition for that was "that the rules of the Stability and Growth Pact are more thoroughly and more aggressively implemented."
Trichet said: "The decisions reached at the summit need a very precise and timely implementation. The euro zone's government leaders have a program, now hard work awaits the governments and European Commission.
"The quick and complete implementation of the decisions is now absolutely decisive," Trichet said.
"The quick and complete enaction of the decisions is now absolutely decisive," he added.
Trichet said that the ECB would track the process closely.
"We now need to see some action," he said.
(Reporting By Erik Kirschbaum)