Pope Francis landed in the Democratic Republic of Congo on Tuesday, hailing his "beautiful trip" to Africa as he comes bearing a message of peace to the conflict-torn nation and its troubled neighbour South Sudan.

Large crowds of well-wishers gathered at Kinshasa's Ndjili airport, about 25 kilometres from the centre, to greet the Argentine pontiff, whose plane touched down at 2.35pm local time.

"We've been waiting for a year, it's a beautiful trip," the 86-year-old pope told reporters travelling aboard his plane.

It is the first time since 1985 that a pope has visited the Democratic Republic of Congo, a desperately poor country of about 100 million people, 40 percent of whom are Catholic.

"I didn't want to miss the opportunity to see him face to face," Maggie Kayembe, a woman in her thirties, told AFP as she waited for the pope. "He always preaches peace wherever he goes, and peace, we really need it," she added.

The six-day trip to DRC and South Sudan had been planned for July 2022, but postponed due to the pontiff's knee pain that has forced him in recent months to use a wheelchair.

He boarded the plane in Rome via an elevator.

Security concerns were also said to play a role in delaying the trip, and a stop in Goma in DR Congo's east, where dozens of armed groups operate, is no longer on the itinerary.

"I would have liked to go to Goma too, but with the war, you can't go there," the pope told reporters on the plane.

On Sunday, he had offered his greetings "with affection to those beloved peoples who await me".

"These lands, situated in the centre of the great African continent, have suffered greatly from lengthy conflicts," he said after his Angelus prayer at the Vatican.

He lamented "armed clashes and exploitation" in DR Congo, and said South Sudan, "wracked by years of war, longs for an end to the constant violence".

As the papal plane flew over the Sahara, the pope held a prayer for "all the people who, searching for a little well-being, a bit of freedom, crossed (the desert) and didn't make it".

He recalled how many people arrive in north Africa hoping to cross the Mediterranean into Europe, only to find themselves "taken to camps, and suffering there. Let us pray for all those people". (AFP)