US Secretary of State John Kerry is urging Democratic Republic of Congo President Joseph Kabila to respect a constitutional law which forbids him seeking a new term in 2016.

“I believe that it is clear to him (Kabila) that the United States of America feels very strongly, as do other people, that the constitutional process need to respected,” Kerry said on a visit to the country on Sunday.

He announced that the United States would provide funding of $US30 million ($A32.46 million) “to support transparent and credible elections as well as recovery … programs in eastern Congo”.

Kerry is on his first major tour of Africa, which is focusing on some of the continent’s most brutal conflicts.

A US official said on Saturday Washington was ready to help fund the demobilisation of some 12,000 rebels active in dozens of militias in the DRC’s mineral-rich, restive east, a plan that is estimated to cost about US$100 million.

The DRC government has gained more control in the conflict-hit eastern areas since a national army offensive, backed by a special UN brigade, forced the powerful M23 rebel group to lay down its arms in November.

Kerry is accompanied on the trip by US special envoy to the Great Lakes region Russ Feingold, who took a leading role in brokering a peace deal with M23 rebels in hostilities which date back to 1994.

“I have no doubt that President Kabila’s legacy will be defined by the progress he has made particularly in the last year in addressing the security of the east,” Kerry said.

He said Kabila “has an opportunity, that he understands, to be able to put the country on a continued path of democracy”.

Kabila became Africa’s youngest leader when propelled into office at 29 after the death of his father in 2001 at the height of a civil war that became known as “Africa’s Great War”.