The Centrists and Christian Democracts (UDC), which also won support from President Carlo Azeglio Ciampi, has given Monday evening as the deadline for a response from the Justice Ministry.
The Justice Ministry is headed by Roberto Castelli of the Northern League party, which follows anti-immigrant and anti-separatist policies. It lies at the heart of most of the rows within the four-way centre-right coalition.
Castelli has so far refused requests from investigating magistrates for more information on the premier’s business dealings.
A billionaire media mogul, Berlusconi is already on trial for allegedly bribing judges during the 1980s relating to a company takeover. The Italian premier denies the charges.
Berlusconi has so far dismissed the current row as petty squabbling even though some of his aides are said to be concerned that constant infighting is taking a toll on his health.
“They’re not serious,” said Berlusconi of the UDC in an published interview. “It’s probably because of the heat,” in reference to the soaring temperatures gripping Italy.
This is not the first time coalition allies have come to blows. Berlusconi described the constant infighting as “just the kids letting off the steam”.
"It's probably because of the heat"
Italian prime minister
But the UDC and the National Alliance of Deputy Prime Minister Gianfranco Fini have fundamental objections to the Northern League and have made it clear they want both the party and its leader Umberto Bossi out of government.
Bossi recently caused waves when he appeared to advocate the use of cannons to prevent illegal immigrants from reaching Italy’s shores.
Rocky EU presidency
The latest crisis caps a tumultuous first month for Italy as the president of the European Union (EU).
There were widespread doubts over Berlusconi’s suitability for the rotating presidency.
These doubts intensified when the premier suggested a German EU lawmaker was suitable for a role of a Nazi concentration camp guard in an address to the EU parliament.
The slurs unleashed a diplomatic row between Rome and Berlin that continues to plague Berlusconi.