BEIJING (Reuters) - No areas will be off limits in talks next week when Chinese Premier Li Keqiang visits Japan, but North Korea is not going to be a focus, a senior Chinese diplomat said on Friday.

China's Premier Li Keqiang speaks with Japanese Association for the Promotion of International Trade head Yohei Kono (not pictured), at the Great Hall of People, in Beijing, China April 9, 2018. REUTERS/Parker Song/Pool

China and Japan, Asia’s two largest economies, have been trying to reset ties after years of increasingly bitter disputes over a group of uninhabited islets in the East China Sea and the legacy of Japan’s invasion of China before and during World War Two.

Japan will host a summit with Li and South Korea’s President Moon Jae-in in Tokyo on Wednesday to discuss regional issues, where North Korea had been expected to be high on the agenda.

The meeting, which has been hosted in turn by each of the three nations since the first held in Japan in 2008, aims to strengthen dialogue and cooperation.

Chinese Vice Foreign Minister Kong Xuanyou said Li’s trip to Japan, the first by a Chinese premier in eight years, represented a “rare development opportunity”, though he admitted challenges remain.

“There will be no off-limits areas,” Kong told reporters, referring to the talks between Li and Abe.

“As long as there are subjects both are interested in, they can be put on the table for candid discussion. (We) hope to increase understanding through discussion, which is helpful to narrowing differences on certain problems.”

While North Korea and other regional issues would come up and would be discussed with both Japan and South Korea so that the three sides could better coordinate policy, the isolated country was not a focus.

“I personally think this China-Japan-South Korea meeting is not to mostly discuss the situation on the Korean peninsula. It’s mainly to discuss regional cooperation between the three,” said Kong, who is also China’s special envoy for the North Korean nuclear issue.

“So I think it will be hard for the three of them to have sufficient time to have deep talks on this issue.”

In a later report, Chinese state media said President Xi Jinping had discussed bilateral ties and North Korea in a telephone call with Abe.

China and Japan should work together to get relations back on track, Xi told Abe.

Bracketing the summit, Li will make a state visit to Japan from May 8 to 11, when he will meet Emperor Akihito, Japan has said.

At Moon’s summit last month with North Korean leader Kim Jong Un, both sides agreed to work towards denuclearisation of the Korean peninsula. Kim is also due to meet U.S. President Donald Trump in coming weeks.

Li will travel to Indonesia before going to Japan.

Indonesia is seeking ways to speed up a $5 billion high-speed rail project being built by a consortium of local and Chinese state firms which faces obstacles over land ownership issues.