Further help to weaker euro zone members would push Italy's public debt higher, Italian Finance Minister Vittorio Grilli was quoted as saying in an interview with daily La Repubblica published on Monday.

Spain could ask for financial aid from the euro zone next month, euro zone officials told Reuters, while Greece is locked in talks with lenders on a further set of reforms in exchange for a new loan tranche.

"Italy would bear the brunt of the cost. Our public debt has already risen by four percentage point due to loans made to Greece, Ireland and Portugal," Grilli told Repubblica.

"If Spain were to obtain aid for no less than 100 billion euros, the Italian share would be equivalent of another 1.5 percent of gross domestic product."

"We must be generous, but we also need to assess with prudence the impact on (our) public finances."

(Reporting By Lisa Jucca/editing by Chris Pizzey)