The Export-Import Bank of China is planning to significantly boost lending to Greek shipowners to help finance new ship orders at Chinese yards, amid signs of a recovery in global shipping following a protracted industry downturn.

The state-controlled bank, already the biggest single lender to Greek shipowners, is expected to announce the new $300 million loan facility later this month during a visit to Greece by Chinese Prime Minister Li Keqiang, according to two people familiar with the issue.

With the new credit facility, the Exim Bank’s overall exposure to Greece will total $1.3 billion. It follows a similar commitment by the bank last year, when the bank pledged to lend Greeks some $230 million for new ship contracts during a visit by Greek Prime Minister Antonis Samaras to China.

“Greek owners make up the bulk of Exim’s shipping portfolio, and I expect that that shipping portfolio will grow in the future,” said one of the people familiar with the financing arrangements.

Commercial relations between Greece and China have deepened over the past several years, particularly in shipping, where Greeks hold a commanding share of the world’s oceangoing fleet and increasingly use Chinese shipyards to build new vessels. Greek shipowners are the biggest clients at those yards, and also the biggest borrowers from Chinese banks to help finance those new vessels.

In 2010, during a visit to Athens, former Chinese Premier Wen Jiabao pledged $5 billion in loan guarantees to Greek shipowners. Since then, Chinese banks have extended some $2.7 billion to Greek shipping companies. Apart from China’s Exim Bank, lenders China Development Bank Corp. and China Everbright Bank Co. have committed more than a billion dollars as well.

The visit this month by Mr. Li is seen as bringing a further deepening in those bilateral relations. A subsidiary of state-controlled China Ocean Shipping Group Co., or Cosco, already operates the main container terminal at the Athens port of Piraeus and has expressed its interest in acquiring a majority stake in the port that Greece is selling off as part of its privatization drive. Given its established operations, Cosco—one of six bidders—is the early favorite for the tender, two people with knowledge of the process said.

Both the port tender and the new financing arrangements come as the global shipping industry claws its way back from a steep, five-year-long downturn that was a consequence of the global financial crisis. During the depths of the downturn, new shipbuilding orders fell dramatically while freight rates all but collapsed to historically low levels.