Business leaders say the March 17 holiday will cost them too much in difficult economic times, while Premier Silvio Berlusconi's ally, the autonomy-minded Northern League party, is lukewarm at best and the head of the predominantly German-speaking South Tyrol doesn't want any part of it.
"We didn't choose to become part of Italy," the region's president, Luis Durnwalder, told state TV on Thursday, pointing out that the Alpine area was stripped from Austria at the end of World War I.
The idea behind the birthday celebrations was to show that Italy has overcome its traditional regional divides - especially between the wealthy north and the underdeveloped, mob-ridden south.
But there has been a steady drumbeat of opposition even as heroic pictures of Giuseppe Garibaldi and other heroes of the Italian Risorgimento have been going up on public buildings and concerts and other anniversary events are being organized.
The dream of unity can't mask the differences in a country where until a few decades ago classified housing ads in the north said "NM" - meaning no southerners - and a recent hit film "Benevenuti al Sud" ("Welcome to the South") depicts the adventures of a postal worker transferred from Milan to Naples' "exotic" Campania region.
The Northern League, a powerful force from Turin's Piedmont area across to Venice, has toned down a separatist drive in recent years, but is pushing hard for a federal tax system to keep more of its own revenue away from the government in Rome and what it sees as the wasteful south.
It has its own green flag, which made national news last fall when a school in Lombardy flew it instead of the Italian tri-colored banner.
Northern League party leader Umberto Bossi said recently that "depending on the location, the holiday will be viewed in a different way."
The government has set March 17 - the day in 1861 when parliament proclaimed Victor Emmanuel II the first king of Italy - as a holiday. It also invited all European Union leaders, President Barack Obama and other world figures to another celebration in Rome on Italy's national day June 2.
Declaration of next month's holiday has already caused a stir.
"March 17 is a day like any other," Federica Guidi, head of the young industrialists' association, told reporters Thursday in Bologna, pressing the idea that the day should be marked by working. "In our country what everyone needs to do is work more."
The government itself is now divided and might backtrack from the initial idea of a national holiday that closes schools and businesses.
Education Minister Mariastella Gelmini said the schools should be open March 17 with special lessons on the meaning of the day. "Otherwise, it's just another holiday," she told the leading Corriere della Sera newspaper.
Just what the meaning is has been subject of debate.
This week, at the Bologna center of Johns Hopkins University, leading history professor Adrian Lyttelton lectured on "How Italy became a nation-state: miracle or disaster?"
His conclusion: While circumstances at the time that brought unification were miraculous, the north-south divide "has to be seen as a failure."