Italians have begun voting in four referendums that could strike a new blow against the prime minister, Silvio Berlusconi, who is still reeling from heavy local election losses last month.
In the run-up to the two days of voting which began on Sunday, the centre-left opposition led a spirited campaign to get the voters out to cast their ballots on a series of issues.
Voters are being asked to consider nuclear energy, the privatisation of water utilities and whether government ministers can be exempt from attending trials against them.
A central issue will be whether enough voters turn out to ensure the necessary quorum of 50 per cent plus one vote.
But if they repeal existing laws by voting yes, the result will probably have repercussions on Berlusconi's fractious centre-right coalition.
"Behind the numbers lies the political fate of those who have taken a stand," Il Sole 24 Ore, Italy's leading business daily, said on Sunday.
"It's clear that a wave of 'yes' votes will result in a shock, perhaps the final one, for his (Berlusconi's) premiership and even for his leadership of his party."
The polls close on Monday at 1300 GMT.
At 1000 GMT on Sunday, up to 12 per cent of eligible voters had cast ballots, which gave the opposition encouragement that the quorum would be reached by Monday afternoon, when the two days of voting ends.
A quorum would be a setback to Berlusconi because he has said he would not vote and some of his ministers have urged voters to boycott.
For some, the votes will be a way to demonstrate their disappointment with Berlusconi himself, who is facing a sex scandal and three fraud trials.
If the quorum is reached, it would mean that "more than half of Italians are pointing a finger against him", Il Sole said.
The referendum on nuclear power is the most emotive of the four, in the wake of the disaster at Japan's Fukushima reactor in March.
Polls say most Italians are against nuclear energy, which they consider unsafe in a country prone to earthquakes.
Nuclear power proponent
Berlusconi is a big proponent of nuclear power, which the centre right says is indispensable for the future of a country that imports nearly all its energy.
Last year the government passed a law to restart a nuclear energy programme, which was halted in 1987 by another referendum.
Aware of the likely backlash following Fukushima, the government has suspended the plans but a referendum could block atomic power for decades.
Another referendum would repeal the "legitimate impediment" that allows ministers to skip trial hearings against them on if they are on government business, which Berlusconi's critics say is for his personal benefit.
Two others concern the privatisation of water utilities. The government says privatisation is essential to finance better services. Opponents say it would just lead to higher prices.
Source: Al Jazeera and agencies