Four lions who went on the prowl in Kenya's capital Nairobi after escaping from a national park have returned to the reserve, rangers said Saturday, after a day-long hunt for the big cats.

Kenya Wildlife Service (KWS) issued an appeal on Friday, with armed rangers and KWS vets with dart guns scouring bush and farmland alongside the capital's Kibera district, one of Africa's largest slums, for the predators.

KWS also used helicopter to search for the lions, who returned home to Nairobi National Park on Friday of their own accord.

"The lionesses and cub are safely back into the park," KWS spokesman Paul Udoto said. "All is well that ends well."

Lions, buffalo and rhino run free in Nairobi National Park, which is spread over 117 square kilometres (45 square miles), just seven kilometres from the bustling high-rise city centre.

While the park is fenced in on the city side -- some bars even have terraces where customers can view animals while downing a cold drink -- it is unfenced on other sides to facilitate the annual wildlife migration in search of grazing.

It is not the first time lions have scarpered into town.

The big cats are under growing pressure as one of Africa's fastest growing cities creeps onto ancient migration routes and hunting grounds.

Lions are estimated to have declined in number by as much as three-quarters since 1980, and to occupy less than a tenth of their historic range across Africa.