COLOMBO: Sri Lanka has rejected China's request to dock one of its submarines in Colombo this month, two senior government officials said on Thursday as the Indian Prime Minister Narendra Modi landed in the island nation.

Sri Lanka last allowed a Chinese submarine to dock in the capital of Colombo in October 2014, a move that triggered fierce opposition from its northern neighbour India, which worries about growing Chinese activity in a country it has long viewed as part of its area of influence.

Modi arrived in Sri Lanka on Thursday for a two-day official visit.

A senior Sri Lankan government official said China's request to dock one of its submarines in Colombo this month had been rejected. He said Sri Lanka was "unlikely" to agree to China's request to dock the submarine at any time, given India's concerns. The official asked not to be named because of the sensitivity of the matter.

The second official, at the defence ministry, also said China's request to dock this month had been rejected but that a decision on a further docking had been postponed.

"It might happen later," the second official told Reuters, adding that China had requested approval to use the port around May 16 "sometime back".

A source close to the Chinese embassy in Colombo confirmed that China had requested permission for the submarine visit but was still awaiting a response.

China has invested heavily in Sri Lanka in recent years, funding airports, roads, railways and ports, unsettling India, traditionally the closest economic partner of the island nation of 21 million people.

More than 70 percent of the trans-shipment in Colombo port comes from India.

Sri Lanka is finalising a plan to lease 80 percent of its loss-making Hambantota port to China for 99 years, but the deal has been delayed because of opposition from trade unions.

The Sri Lankan government also wants to establish a petroleum hub with the help of India in the eastern port city of Trincomalee, where Lanka IOC, the subsidiary of Indian Oil Corporation, handles 15 out of 99 oil tanks.

A 1987 accord between India and Sri Lanka provides that their territories not be used for activities deemed prejudicial to each other's unity, integrity and security.