* Third party agreements hinder Wind Tre grid sale to EQT- sources

* Deal values Wind Tre's telecoms grid at 3.4 bln euros

* Deadline for completion extended to next February

* Italian telecoms market being reshaped by M&A moves

MILAN, Nov 15 (Reuters) - The completion of the sale of a majority stake in Italian telecoms firm Wind Tre's telecoms grid is facing hurdles linked to separate network agreements with rival operators Iliad and Fastweb, two sources close to the matter told Reuters.

Sweden's EQT Infrastructure announced in May it would take control of the telecoms network of Wind Tre, part of Hong Kong conglomerate CK Hutchinson, in a deal valuing the grid business at 3.4 billion euros ($3.7 billion).

The finalisation of the sale had been expected within six to nine months, EQT said at the time.

However, in a statement issued this month, CK Hutchinson said the deadline to close the deal had been extended by three months until Feb.12, 2024 due to the lack of an agreement "with relevant third parties".

The sources said the postponement was needed due to complex talks with French group Iliad, which has a joint venture agreement with Wind Tre involving parts of the mobile network serving less populated areas of Italy.

Iliad and Wind Tre teamed up to share the costs of rolling out fifth-generation mobile networks (5G) across more remote areas of the country setting up a 50-50 joint venture, comprising some 7,000 antennas. Such an agreement includes change of control clauses, one of the sources said. The grid sale delay is also linked to ongoing negotiations with telecoms firm Fastweb, the sources said, adding talks are leaning towards a positive outcome. Fastweb is also in a long-term 5G network sharing partnership with Wind Tre in Italy. CK Hutchinson said in the statement that relevant third parties' consent is needed to complete the deal and remained open to considering proposals, without adding further details.

Wind Tre, Iliad, EQT and Fastweb declined to comment. CK Hutchinson did not immediately respond to a request seeking comment.

The Italian telecoms sector is being reshaped by M&A, with market leader Telecom Italia having agreed to sell its main network grid, while Vodafone is considering a range of options for its struggling business in Italy. ($1 = 0.9206 euros) (Reporting by Elvira Pollina)