Voters in the wealthy northern Italian regions of Lombardy and Veneto are heading to the polls to decide if they want to seek greater autonomy from Rome.

While the twin referendums are non-binding, a resounding "yes" vote would give the presidents of the neighbouring regions more leverage in negotiations to seek a greater share of tax revenue and to take more responsibility from Rome.

The leaders want more powers in areas as security, migration, education and the environment.

Lombard president Roberto Maroni has lowered expectations, saying he would be happy with a 34% turnout among the region's 7.5 million voters, equal to the national turnout in a 2001 referendum.

The Veneto autonomy drive will die if voter turnout is below 50% plus one of the region's 3.5 million voters.