North Korean leader Kim Jong-un has sent a stern warning to top authorities in Pyongyang hinting at more purges in the coming months as the reclusive ruler sports a new hairstyle.

Kim, who is thought to be in his early 30s, asked the authorities of the Workers' Party to launch a "campaign against abuse of power, bureaucratism, irregularities and corruption".

According to a party resolution, adopted at a politburo meeting, carried by the Korean Central News Agency (KCNA), Kim "underlined the need for the officials to devote their blood and sweat to solving knotty problems in the people's living and difficult problems of people, deeply aware of the noble intention of Kim Jong-un who is dedicating himself to the people".

The meeting was held to review the three-year rule of the new leader, who took the baton from his father Kim Jong-il.

The resolution called for "conducting the work for implementing the behests of Kim Jong Il as the primary tasks and unconditionally carrying out them to the last without an inch of deflection and a single step of concession".

The message has come at a time when Kim is tightening his grip on the isolated country's power through a series of removals.

Kim removed and executed a general last month who seemed to have lost the leader's faith.

He also executed his uncle Jang Song Thaek, who was once a powerful figure in North Korean affairs. In 2013, he got rid of many of his supporters for alleged anti-state activities.

Meanwhile, the latest images published by the state-run media show Kim's new hairstyle: relatively high hair and shrunken eyebrows.