North Korean leader Kim Jong-Un visited a ski resort under construction in the northeast of the country to check on the progress of his pet project, state media reported, just days after he had his uncle executed.

The Masik Pass Ski Resort made headlines in August when Switzerland blocked a $7.6m sale of ski lifts to Pyongyang, calling it a "propaganda project" for the regime.

Featuring 110 km of multi-level ski runs, a hotel, heliport and cable cars, the resort has been heavily promoted since Kim visited it in June and called for construction to be completed by the end of the year.

On his latest trip, the young leader praised soldiers and labourers for helping speed up construction under "biting cold in December", official state news agency KCNA said on Sunday, adding the project was "near completion".

"He (Kim) said the skiing courses on the Masik Pass Ski Resort are world-class ones in terms of their number and total length," it said.

The project was now "at the centre of the world's attention", Kim was quoted as saying, adding "everyone would marvel" at its magnificence.

He also urged operators to illuminate the resort at night to allow visitors to enjoy skiing and skating after dark, in an impoverished country suffering chronic power shortage.

Kim's reported trip came days after the shock execution Thursday of his powerful uncle and political mentor, Jang Song-Thaek.

Jang was put to death four days after he was ousted from all his party and military positions for charges including corruption and plotting to overthrow the state.

The purge was the biggest political upheaval since Kim, aged around 30, took power after the death of his father and longtime ruler, Kim Jong-Il, in December 2011.

The young leader has shown a fondness for expensive, high-profile leisure projects in and around the showpiece capital Pyongyang including a massive new water park, an amusement park and a luxury horseback riding club.

The Munsu Water Park in Pyongyang opened in October to much fanfare, with the 109,000-square metre venue sporting dozens of indoor and outdoor pools, water slides and saunas.

Kim in September also watched films at a new "4D" movie theatre built in the newly-renovated Rungna People's amusement park, state media reported earlier.

He was photographed riding a roller coaster in the Rungna amusement park in Pyongyang when it reopened in July 2012 after renovations ordered by Kim.