The leader of Italy's Northern League is threatening to pull Italy apart if his devolution demands are not met.
Bossi became renowned for his secession campaign
Umberto Bossi, reforms minister in the ruling coalition, told Radio Padania either "federalist reform is carried out or we go right back to secession".
Last month the Northern League agreed to delay until next January a decision on whether to quit the coalition.
Secession from Italy was a key part of Mr Bossi's platform in the 1990s, but he later softened his position.
Speaking on the League's Radio Padania on Thursday he said: "I hope that some have not mistaken our moderation... as meekness, because this time either a federalist reform is carried out or we go right back to secession, and it will be a hard secession."
He added: "We will start heating up this machine already at our next rallies by telling people that if there is no federalism the hard fight for secession will resume."
At last month's party meeting Mr Bossi said there was no point in staying if devolution reforms were not passed by the end of the year.
The proposed reforms give increased autonomy and legislative powers to the regions and health, education and local policing and set up a chamber of the regions to replace the Upper House, the Senate.
As these involve constitutional changes, a series of separate votes in both houses are required and the entire process will take many months.
Mr Bossi has called on his supporters to mobilise mass demonstrations to keep up the pressure on the government over the federalism law.
The other junior coalition partners, the post-Fascist National Alliance and the small Catholic party, the UDC, are furious at what they see as preferential status given to Mr Bossi by Prime Minister Silvio Berlusconi and his Forza Italia Party.
Correspondents say many ordinary Italians think the infighting is distracting the government's attention from pressing issues, such as the cost of living and unemployment.