A Chinese border province has announced plans to beef up transport and trade links with North Korea, including new railways to the frontier, soon after pledges by Beijing to implement tough new UN sanctions.

China has been North Korea's sole major ally for decades and is overwhelmingly its biggest trade partner, but has come under increasing pressure to join in global sanctions aimed at punishing Pyongyang for repeated nuclear and missile tests.

The blueprint by the Jilin provincial government, in northeast China, calls for "hastening the construction of express railways from key cities such as Changchun to major border cities" and improving rail links from Tumen on the frontier to Rason and Chongjin in North Korea.

The plan calls for the "unimpeded passage of through transport by rail and sea".

There is also a proposal to open a road linking Tumen and North Korea, according to a release published on the government's website Monday, which details plans to strengthen links with other Northeast Asian countries by 2020.

Rason and Chongjin are on North Korea's northeastern coast, on the Sea of Japan (East Sea). Changchun, the capital of Jilin, is in the centre of the province while Tumen is in the northeast, in an ethnic Korean autonomous area.

Earlier this month, Beijing worked with the United States to craft a UN Security Council resolution targeting North Korea's efforts to raise funds to finance its nuclear programme.

Industrial cooperation as detailed in the Jilin plan does not violate sanctions against the North and can play a positive role, Jin Qiangyi, director of the Asia Research Centre at Yanbian University in the province told China's state-run Global Times newspaper Wednesday.

"Keeping some pressure on North Korea by resorting to sanctions is necessary to prevent it from further missile and nuclear tests, but the international community should also maintain engagement with Pyongyang and encourage it to integrate into the world," he said.