Investigators of the United Nations have revealed that one of the four remaining genocide fugitives, who sought for their role in the 1994 Rwanda genocide, Fulgence Kayishema, has been arrested in South Africa.

The International Residual Mechanism for Criminal Tribunals said in a statement that Kayishema was arrested in Paarl, South Africa in a joint operation.

"Kayishema directly participated in the planning and execution of this massacre, including by procuring and distributing petrol to burn down the church with the refugees inside," the statement said.

"When this failed, Kayishema and others used a bulldozer to collapse the church, burying and killing the refugees inside.

"Kayishema and others then supervised the transfer of corpses from the church grounds into mass graves."

Around 800,000 Rwandans, most of them ethnic Tutsis, were slaughtered over 100 days at the hands of Hutu extremists.

Kayishema, a former police inspector, faces charges of genocide, complicity and conspiracy to commit genocide, and crimes against humanity.

According to the MICT website the suspect has been on the run since July 2001, which gives his year of birth as 1961.

He and others allegedly murdered more than 2 thousand Tutsi men, women and children who had taken refuge in a Catholic church in Nyange, the Kivumu district.