European Central Bank head Mario Draghi says the euro currency union remains "incomplete" and needs to be strengthened with better oversight of member countries' economic policies.

Draghi said in the text of a speech Thursday in Helsinki that "for all its resilience, our union is still incomplete."

He said the 18 member countries have agreed not to bail each other out through fiscal transfers - so they need other ways of keeping problems in one country from affecting them all.

He called for "joint sovereignty" over economic policies and urged tougher use of the EU's annual review of national budgets, as a way to keep poor economic policymaking from triggering economic trouble in individual countries.

EU officials are currently reviewing national budgets. They are due to decide before the end of the month whether to fine some countries like France and Italy for not meeting targets.

Draghi also called for more cross-border integration of financial markets and bank lending. That way, any troubles would be eased by being spread across shareholders and financial institutions in the currency union as a whole.

The eurozone is struggling to emerge from a debt crisis that began in 2009-10 with troubles in smaller countries such as Greece, Ireland and Portugal and led to fears the currency union might break up. Markets are calmer now and breakup fears have receded. But the eurozone as a whole is still mired in low growth and high unemployment.