North Korean leader Kim Jong-Un took his stylish wife and powerful sister to a make-up plant for a "field guidance trip" amid the country's nuclear standoff with the US.

During a visit to the Pyongyang Cosmetics Factory in the capital, Kim hailed its "world-level" products that realised "the dream of the women who want to be more beautiful", the official KCNA news agency reported.

Kim was accompanied by Kim Yo-Jong, his younger sister and a senior member of the ruling Workers' Party, it said, with photos showing Kim's wife Ri Sol-Ju following him at the factory in a floral pattern dress. 

The two are seen as the most powerful women in the isolated, deeply patriarchal nation. 

They have often accompanied Kim to official events since he took power in 2011, in a break from the past when former leaders' spouses or sisters rarely made public appearances.

Ri, a former star singer also known for her affinity for luxury fashion, is known to have three children with Kim. 

Yo-Jong, believed to be in her 20s, was promoted earlier this month to be an alternate member of the party's powerful politburo -- the decision-making body presided over by her brother. 

Known to be handling the party's propaganda operations, Yo-Jong has been seen accompanying Kim closely and in a casual manner -- rare among the country's top officials -- at high-profile public events. 

Both Kims were born to the late ruler Kim Jong-Il and his third partner Ko Yong-Hui, a former dancer.

At the factory they viewed a mosaic of their father entitled "To Provide Our People with Better Cosmetics", KCNA reported Sunday.

The Kim family has ruled the impoverished but nuclear-armed state with an iron fist through three generations since the nation was established in 1948.

Tensions have been high on the peninsula with the North conducting its sixth nuclear test in September and launching multiple missiles capable of reaching the mainland of its "imperialist enemy" the US. 

Kim and US President Donald Trump have traded threats of war and personal insults against each other in recent months, sparking global alarm.