The source said the purchase of further Telecom Italia (TIM) shares depended on the phone group's new business plan.

On Thursday CDP, which has a stake in TIM of just under 5 percent, said its board had approved the purchase of additional shares but gave no further details.

A source close to the matter said on Thursday it could raise its stake to up to 10 percent in the next 12 months.

(Reporting by Stefano Bernabei, writing by Stephen Jewkes)