A woman is reflected in a glass showcase as she walks past a scale replica of a COSCO cargo ship at the company's headquarters in Beijing November 8, 2013 file photograph. [Photo/Agencies]

Cosco's offer was a 70 percent premium to the closing share price of Piraeus Port of 12.95 euros Wednesday and values the entire business at 550 million euros. Piraeus Port shares rose as much as 8.8 percent in trading on the Athens exchange today.

The Piraeus sale is also seen as a yardstick in Greece's lacklustre state asset sales program, a key revenue-raiser tied to the country qualifying for billions in rescue funds from its European partners and the International Monetary Fund. Last month, the government wound up previously agreed deals for the privatization of 14 regional airports and the sale of seaside resort in Athens. Both those deals had been halted when Tsipras came to power last year.

Cosco's supremacy at Piraeus is thought to be a prerequisite to unleashing more Chinese investment in Greece, where unemployment has soared and foreign investment dried to a trickle amid six years of political turmoil and concerns of financial collapse.

Because the Mediterranean is a key European entry point for Chinese products such as clothing, manufacturing machinery, household appliances, vehicle parts and industrial yarn, as well as automobiles from Japan and South Korea, Piraeus Port has more potential to attract international shipping companies to set their regional transit centers and service branches.

Greek officials expect Chinese investment in projects such as a major freight and logistics center on the outskirts of the Greek capital and a new airport planned for the island of Crete.

"A new day is dawning for the port of Piraeus and the country: jobs for all and income for the state, as Cosco has already shown," Michalis Nomicos, the president of Donomis Cruise Services said in a statement. "It's a given that cruise services and Piraeus's competiveness in the Mediterranean will improve."

The transaction will be two-step deal: Cosco will buy a 51 percent stake in Piraeus for 280.5 million euros and will acquire the additional stake in the next five years for 88 million euros on completion of the terms in the shareholder agreement, including investments.

Cosco agreed to mandatory investments of 350 million euros in the next 10 years and the income accruing to the Greek state from the concession agreement of some 410 million euros. The amount includes expected revenue from dividends and additional investments up to the end of the concession agreement in 2052.

Of the mandatory investments, 300 million euros will be spent in the first five years, mainly in relation to cruise and ship repairing operations. Officials expect Cosco could spend another 270 million euros in investments up to 2052. They said Cosco had originally bid 17.5 euros a share for the stake.

Maria Petrakis is a freelance writer based in Athens. She contributed this story to China Daily.