HONG KONG, Nov 25 (Reuters) - China Rongsheng delivered on Friday the first of 12 mega bulk carriers to mining giant Vale SA, which the Brazilian firm has indicated could be the first such ship to carry iron ore to the world's largest steelmaker.

China has yet to allow any of Vale's giant ships to dock at its ports, forcing the world's biggest iron ore producer to send its vessels instead to Italy, Oman and other destinations.

"We have just delivered our first 380,000-tonne very large ore carrier (VLOC) to Vale this afternoon," said Michael Cheng, spokesman for China Rongsheng Heavy Industries.

Vale has said the Rongsheng-built ship, Vale China, would have a Chinese port as its first commercial destination. The firm's chief executive, Murilo Ferreira, attended the ship's formal launch ceremony in Nantong in July.

The company said in September it was still negotiating to gain access to Chinese ports and was confident an agreement would soon be reached.

 The Brazilian firm plans to operate as many as 35 VLOCs before the end of 2013, owning at least 19 of them, with the rest chartered from Bergsen, STX Pan Ocean and Oman Shipping. Rongsheng has a contract to build 12 of the ships by the end of next year, worth as much as $1.6 billion.

"Construction of all (Vale) ships has started and there is no such case of cancellation. Four ships will soon start trial voyages," said Rongsheng Chief Executive Chen Qiang.

The mega ships, which are also being built by Korea's Daewoo Shipbuilding and China's Bohai Shipbuilding Heavy Industry, will cut freight costs from Brazil to China by 20 to 25 percent and will significantly reduce carbon emissions compared with other vessels, Vale said.

Vale currently operates at least two VLOCs, the Vale Brasil and Berge Everest, which were delivered earlier this year.

The Vale Brasil in June failed to gain access to Chinese ports on its maiden voyage and was forced to divert to Italy. (Writing by Randy Fabi;Editing by Clarence Fernandez)