Italian Prime Minister Matteo Renzi has resigned after suffering a heavy defeat in a referendum over his plan to reform the constitution.

In a late-night news conference, he said he took responsibility for the outcome. He said the No camp must now make clear proposals.

An exit poll for state broadcaster RAI suggests 42-46% voted to back reform, compared with 54-58% voting No.

The first projections based on the official count point to a wider defeat.

Early indications have the Yes vote at 39-43% and the No at 57-61%.

"Good luck to us all," Mr Renzi told reporters. He said he would tell a Cabinet meeting on Monday afternoon that he was resigning, and then tender his resignation to the Italian president after two-and-a-half years in office.

The president is expected to ask him to stay on at least until parliament passes a budget bill later this month.

Renzi said the reforms he proposed would have cut Italy's bureaucracy and made the country more competitive.

But the referendum was widely seen as a chance to register discontent with the prime minister.

(BBC)