Russia and the Democratic People's Republic of Korea have reopened a rail link that Pyongyang hopes will offer it a trading boost.

The 54-kilometer track from the Russian border town of Khasan to the DPRK port of Rajin was opened for service at a special ceremony on Sunday, Pyongyang's KCNA news agency reported.

Rajin is the centerpiece of the Rason Special Economic Zone, established by the DPRK in 1991.

Located in the far northeast where the DPRK borders Russia and China, Rajin was chosen because of its potential as a warm-water port for the DPRK's two giant neighbors.

At a summit in 2001, Pyongyang's then-leader Kim Jong-il and Russian President Vladimir Putin agreed to restore the rail link as part of a joint project that included a container terminal in Rajin.

Work on the railway line began in 2008.

Since receiving special economic zone status more than two decades ago, Rason has largely failed to fulfill expectations, but development activity there has gained momentum in the last few years.

Rajin's potential as a lucrative trading hub is an increasingly attractive prospect for a country burdened by a raft of international sanctions imposed over its nuclear weapons program.

Initially, the rail link will transport Russian coal supplies to Asia-Pacific markets.

The initial vision was for the Khasan-Rajin link to eventually become part of the so-called "Iron Silk Road" - a rail network spanning Asia and Europe.

But that idea envisages a train service linking the entire Korean Peninsula - a project that looks like it is being held permanent hostage to volatile relations between the DPRK and the Republic of Korea.