Chinese Premier Li Keqiang on Friday said Piraeus could become one of the world's "most competitive" ports if China shipper COSCO is able to fulfil its investment plan for the area.
"We hope to turn Piraeus...into one of the most competitive ports of the world," Li, on a three-day visit to Greece, said as the first rail shipment of Chinese goods left the port for central Europe.
COSCO, which in 2008 signed a 35-year concession to expand the two main container terminals at the port, plans to pour $230 million (170 million euros) in expansion works by 2020.
The additional infrastructure is calculated to increase the port's capacity to over 6.0 million container units, from 3.16 million last year, officials said on Friday.
The deal is subject to approval from the European Union, which has yet to give its consent.
"There is still much under discussion (concerning Piraeus)," Greek Prime Minister Antonis Samaras said in welcoming Li on Thursday.
"I believe that Europe itself understands that Greece constitutes a natural maritime link to China," he said.
China is also interested in a 67-percent stake in the Piraeus port authority, which is being sold by the Greek state under the EU-IMF bailout agreement contracted to avert Greece's bankruptcy in 2010.
Reportedly, Brussels is not keen to see China increase its hold on Piraeus, one of the busiest ports in the Mediterranean in terms of commerce but also tourism traffic.
- Piraeus a 'pearl' -
"The port of Piraeus can become a Chinese gateway to Europe. It is like a pearl in the Mediterranean Sea," said Li, on his first trip to southern Europe since becoming premier.
Samaras said the port's newly-completed rail connection opens up new prospects.
"We calculate goods can be transported (via rail from Piraeus) to central Europe and Germany eight days sooner than any other port," said George Gratsos, president of the Hellenic chamber of shipping.
Li will next travel to Crete, where the airport of Kasteli has been cited as a potential investment target for China.
The last visit by a top Chinese official to Greece -- by then premier Wen Jiabao -- was in 2010, at the start of the European country's crippling economic crisis.
The selection of COSCO in 2008 to expand the container terminals at Piraeus made waves, but subsequent efforts by the Greek state to secure Chinese investment -- including in public railways and the Athens airport -- saw little success.
But with the spectre of Greece going bankrupt and a breakup of the euro receding, Chinese investors have begun to show renewed interest.
On Thursday, the Chinese delegation signed over a dozen trade and investment deals worth some $4.6 billion.
The deals included multi-billion-dollar Chinese bank loans to build at least 10 Greek-owned ships in Chinese shipyards.
 Greek shipowners -- who account for more than 16 percent of the global fleet -- currently have orders for 220 new ships in China, China Development Bank vice president Zheng Zhijie told a marine conference later on Friday.
Agreements were also signed on the construction of solar energy parks in Greece, and trade deals involving marble, granite, wine and olive oil.
Earlier this year a group including Chinese conglomerate Fosun was selected to lead a 6-billion-euro ($8.1 billion) redevelopment of the old Athens airport of Hellinikon into a housing and leisure complex.