By Agence France-Presse
Ri Yong Ho's visit comes ahead of planned nuclear summits between the North's leader Kim Jong Un and the presidents of South Korea and the United States in the coming weeks.
"Now it's particularly important (for North Korea) to enlist support, including from Russia, to cover its back," said Alexander Vorontsov, a specialist on the region from Moscow's Oriental Studies Institute.
Ri visited Beijing last week for talks with his Chinese counterpart, after North Korean leader Kim Jong Un made a landmark trip to Beijing last month.
Russian Foreign Minister Sergei Lavrov and Ri will discuss ways to resolve tensions on the Korean peninsula, among other topics, Moscow's foreign ministry said.
The ministry hailed what it called "positive trends" in the region, in a statement ahead of the meeting.
The most recent North Korean ministerial-level visit to Russia saw the external economic relations minister visit Vladivostok in September.
Kim was expected to attend 2015 celebrations in Moscow for the 70th anniversary of the end of World War II but opted not to go at the last minute.
The leader's secretive three-day meeting with Chinese President Xi Jinping in March was his first trip abroad since gaining power from his late father in 2011. China is North Korea's main trading partner.
The visit was seen as a gesture of reconciliation after months of high tensions over the North's missile and nuclear programmes.
Kim is due to hold a summit with South Korea's Moon Jae-in on April 27 in the Demilitarized Zone that divides the Korean peninsula, in only the third meeting of its kind.
A landmark meeting with US President Donald Trump is planned to follow -- although no specific dates or venue have been set.
The diplomatic thaw began during the Winter Olympics in South Korea, to which Kim sent athletes, cheerleaders and his sister as an envoy.
The stunning detente with the US comes after North Korea last year fired multiple missiles and carried out its most powerful nuclear test.
Trump in turn hurled insults at Kim, calling him a "madman with nuclear weapons" and said that a military option against North Korea was "locked and loaded".
Moscow backs "direct dialogue" between Pyongyang and the United States and "normalisation" of its relations with Seoul, the Russian foreign ministry said.
If the summits with Moon and Trump are a success, "it will be a turning point, a breakthrough," said analyst Vorontsov.
Kim's foreign affairs chief flew to Moscow on a scheduled flight from the central Asian republic of Turkmenistan on Monday after earlier visiting Azerbaijan, Russia's RIA Novosti news agency reported.
At the airport, Ri did not react to questions from waiting journalists.
Moscow has backed United Nations Security Council resolutions over Pyongyang's nuclear and ballistic missile tests.
But Russia still has relatively warm ties with North Korea, with which it shares a small land border, and provides it with some food aid.
North Korea currently has some 35,000 of its nationals working as labourers in far eastern Russia, particularly in timber felling, agriculture and construction.
The workers are toiling in "slave-like conditions," then-US Secretary of State Rex Tillerson told the UN in December.
Russia is phasing out this programme in accordance with a United Nations Security Council resolution and began to send them home in February, although it refused to send them all at once and they are working out their contracts.