Italian Prime Minister Matteo Renzi says financial markets should not worry about Sunday's referendum on constitutional reform. He insists structural reform is necessary for the country.

"To the financial markets we say that we have always received the message that structural reforms are the principal asset for the future of Italy, I think everyone has always said this everywhere. And we think that structural reform is what this country needs and Italians will decide if they agree or not, on the simplification of institutions that we have proposed," said Renzi.

Renzi on Monday said the changes in the Constitution will end parliamentary deadlocks and help stimulate Italy's stunted economy.

Opinion polls predict Renzi's defeat in the referendum. Opponents say the reforms will weaken democracy and concentrate power in the hands of the prime minister.

Renzi has promised to resign if he does not win the referendum.