Belgium's King Philippe landed in the Democratic Republic of Congo on Tuesday, in a historic visit to the central African country his ancestor once ruled brutally as his personal fief.

The monarch will undertake a six-day trip billed as a chance for reconciliation after atrocities committed under Belgian colonial rule.

The visit comes two years after Philippe wrote to Congolese President Felix Tshisekedi to express his "deepest regrets" for the "wounds of the past."

Tshisekedi and his wife greeted King Philippe and Queen Mathilde on a red carpet rolled out on the tarmac of the international airport of the capital Kinshasa, a sprawling city of about 15 million people.

On Monday, Congolese government spokesman Patrick Muyaya told reporters that Belgium and the Democratic Republic of Congo (DRC) were starting a "new partnership."

King Philippe, seen here in a file picture alongside Queen Mathilde, is making his first trip to DR Congo. The country suffered brutal treatment under Belgian colonial rule
King Philippe, seen here in a file picture alongside Queen Mathilde, is making his first trip to DR Congo. The country suffered brutal treatment under Belgian colonial rule AFP / Lars Hagberg

"We are not forgetting the past, we are looking to the future," he added.

Belgian Prime Minister Alexander De Croo, who is visiting the impoverished nation of 90 million people alongside the king, echoed the sentiment.

"It's a historic moment," he told a Belgian national broadcaster Tuesday, hailing the opportunity to forge future closer ties.

Belgium's colonisation of the Congo was one of the harshest imposed by the European powers that ruled most of Africa in the late 19th and 20th centuries.

King Leopold II, the brother of Philippe's great great grandfather, oversaw the conquest of what is now DRC, governing the territory as his personal property between 1885 and 1908 before it became a Belgian colony.

Belgium is preparing to return to Kinshasa a tooth -- the last remains of Patrice Lumumba
Belgium is preparing to return to Kinshasa a tooth -- the last remains of Patrice Lumumba BELGA via AFP / STAFF

Historians say that millions of people were killed, mutilated or died of disease as they were forced to collect rubber under his rule. The land was also pillaged for its mineral wealth, timber and ivory.

The visit is King Philippe's first to DRC since ascending the throne in 2013. His father, King Albert II, visited the country in 2010.

Belgium is preparing to return to Kinshasa a tooth -- the last remains of Patrice Lumumba -- a hero of the anti-colonial struggle and short-lived first prime minister of the independent Congo.

Lumumba was murdered by Congolese separatists and Belgian mercenaries in 1961, and his body dissolved in acid, but the tooth was kept as a trophy by one of his killers, a Belgian police officer.

According to Belgium's royal palace, the king is also due to discuss the question of returning artworks looted during the colonial era.

Philippe is due to hold a ceremony with Tshisekedi at the Congolese parliament in Kinshasa on Wednesday and then on Friday deliver a speech to university students in the southern city of Lubumbashi.

On Sunday, the Belgian sovereign will visit the clinic of gynaecologist Denis Mukwege, co-winner of the 2018 Nobel Peace Prize for his fight against sexual violence, in the eastern city of Bukavu.

The trip comes at a time of heightened tension between Kinshasa and neighbouring Rwanda over rebel activity in the conflict-torn eastern DRC.

DRC's government has accused Rwanda of backing the resurgent M23 militia, an accusation which Rwanda has denied.