* Next deadline will not be extended

* Sees 2011 core earnings in lower part of guidance

MILAN, Jan 17 (Reuters) - Italian yellow pages group Seat Pagine Gialle urged creditors to agree a restructuring of its 2.7 billion euros ($3.44 billion) of debt, warning it would otherwise go into special administration.

Turin-based Seat said on Tuesday its board would meet shortly, likely by the end of January, to approve a final debt restructuring proposal and set a last deadline.

Seat said that if its final proposal is not accepted, it would make no more extensions and start special administration proceedings under Italy's so-called Marzano law.

"The company wants to establish a definitive timeframe for its final proposal," is said in the statement.

Seat, which has defaulted twice on its debt, also said senior bondholders would join the talks.

Two deadlines to secure an agreement on debt restructuring have passed without a deal backed by all of Seat's senior lenders, a group of about 70 Italian and foreign banks led by Britain's Royal Bank of Scotland.

Approval from all of its senior bank lenders is a condition for the deal to go ahead.

Like other heavily indebted media companies, Seat was trapped in the credit crisis, which made it prohibitive to refinance while Internet competition strengthened and print advertising sales declined.

Seat was bought in 2003 by private equity firms in a 5.7-billion euro leveraged buyout. CVC, Permira and Investitori Associati now hold about 49.5 percent of Seat, whose market value has fallen about 99 percent from its peak in 2007.

In the statement on Tuesday, Seat said 2011 revenue and core earnings will be in the lower part of a range it gave in August. It also forecast 2013 revenue of 720-740 million euros and core earnings of 330-350 million.

• A Permanent Economic Emergency