The Kenya Wildlife Service has launched a study to establish if the Nairobi National Park can safely host its 35 lions.
Director general Kitili Mbathi said they might be forced to move nearly half of the big cats from Nairobi if the survey shows the current number is unsustainable.
The move comes after lions consistently escaped from the park for several weeks, culminating in the killing of two last week.
The park's most popular lion called Mohawk was killed by rangers in Isinya on Wednesday, while villagers in Kajiado downed another named Lemek the next day when it attacked livestock.
“We may have to half the population because the dispersal area for the park has been taken over by settlements. The lions would be taken to other parks like Rimoi,” Mbathi said at KWS headquarters yesterday.
The traditional carrying capacity for Nairobi has been 35 lions, but the number is likely to go down because of the growing city and shrinking park area.
Mbathi also confirmed fears the park could in future be fenced completely, turning it into a naturalistic zoo.
Currently, the southern end is open to allow animals migrate to Amboseli in search of pasture during the dry season.
He said the park is being constricted in the south by private landowners who have built houses around Kitengela.
Mbathi said herbivores, such as zebras and antelope, which lions hunt, normally disperse through this path, but when lions follow them they stumble into human settlements.
Mbathi, a career banker who took over at KWS early this year, said the animals are also increasingly being distressed by the construction of the bypass near Wilson Airport, where an electric fence was removed.
Nairobi is the oldest and smallest park in Kenya, extending over 117 square kilometres.