ATHENS (Reuters) - Vodafone Group plans to speed up the development of 4G technology in Greece as part of its strategy to use proceeds from its Verizon deal to upgrade networks in Europe, Chief Executive Vittorio Colao said on Friday.

"Vodafone is committed to this country, to Greece," Colao told reporters in Athens after meeting Prime Minister Antonis Samaras. Vodafone is the second-biggest operator in Greece behind Cosmote, a unit of Deutsche Telekom.

"Vodafone is about to accelerate investment in 4G technology in the country," Colao said.

Revenues for mobile phone operators in Greece have been falling as a result of the severe austerity, acute competition and regulatory pressures on prices.

Under its "Project Spring" plan which follows the $130 billion (82 billion pounds) sale to Verizon of its 45 percent stake in Verizon Wireless, the British company intends to increase capital spending by a further 6 billion pounds over three financial years to improve its network quality in European countries and emerging markets.

Colao said last week that Vodafone, the world's second largest mobile operator by revenue, would direct a large part of the "Project Spring" investment spending towards Italy, one of its largest markets in Europe following the Verizon deal.

"This is a sign of confidence in the digital world and in Greece, and I'm very pleased with the early results and of (the) trust that Vodafone customers are expressing in this strategy," Colao said on Friday in Athens.

In a bid to challenge Cosmote's market leadership in Greece, Vodafone tried but failed last year to merge with the country's third-biggest operator, Wind Hellas.

The two firms subsequently struck a network-sharing agreement in June this year to save costs.

(Reporting by Harry Papachristou; Writing by Karolina Tagaris; Editing by Greg Mahlich)