Children at a kindergarten dressed in Korean costume, their cheeks painted with North Korean flags, in anticipation for his visit.

The Vietnam-Korea Friendship Kindergarten is a relic of the once-close ties between Vietnam and North Korea in the aftermath of the war with the United States. It opened in 1978 with funding from North Korean founder Kim Il-sung.

Its classrooms are named after North Korean leaders. Portraits of Kim Il-sung and Kim Jong-il gaze down from the walls.

While most of the 500 students are Vietnamese, links with North Korea are kept up with visits from the children of the North's consular staff. Waitresses from the Pyongyang Restaurant in Hanoi even taught the children Korean dance.

North Korean newspapers on Saturday trumpeted that Vietnamese President Nguyen Phu Trong hosted a banquet for Kim on Friday, and Kim later held talks with Prime Minister Ngyuen Xuan Phuc.

Kim said he wanted to increase economic, technonology and defence cooperation with his hosts.

"It is the unwavering position of our country and our party to inherit through generations the friendly cooperative relations between the two countries and the two parties based on blood," he said.

Kim Il-sung visited Hanoi twice, in 1958 and 1964, and Ho Chi Minh also visited Pyongyang.

North Korea's ambition to increase economic ties with Vietnam fits with rapidly improving relations between the North and South Korea.

South Korea is the second-biggest foreign investor in Vietnam and overtook the US as Vietnam's second-largest trading partner in 2017.

Technology giant Samsung manufactures in Vietnam, and many other South Korean companies shifted manufacturing out of China and into Vietnam in the wake of a diplomatic dispute over the THAAD missile shield.

South Korean President Moon Jae-in said on Friday he would discuss with the US ways to reopen tourism exchanges between the two Koreas and reopen the joint Kaesong Industrial Complex on the North Korean border.

Moon said in a speech he wanted economic cooperation between Seoul and Pyongyang.

But it is unclear how this can happen while US and United Nations sanctions on North Korea remain in place.

The Hanoi summit failed to reach a deal to lift any sanctions.

North Korean waitresses working abroad to send cash home to the North Korean government, such as those who had regularly taught at the kindergarten, are also hit by sanctions.

Kim left Hanoi on Saturday after visiting the Ho Chi Minh mausoleum.

By Kirsty Needham - The Age (.au) - March 2, 2019