* Hollande warns of religion-based conflict
* French to send more troops by end of the year
* Zuma stops short of committing more soldiers
French President Francois Hollande said on Monday the collapse of the Central African Republic could destabilise the region, as he sought to drum up support for increased military intervention while on a state visit to South Africa.
France committed on Sunday to increasing the number of troops in its former colony by year-end, under a U.N. resolution, to help prevent the state spiralling out of control with the risk the power vacuum could encourage militancy.
The Central African Republic has descended into chaos since mostly Muslim Seleka rebels ousted President Francois Bozize in March, the latest coup in the poor but mineral-rich country.
"There is a political emergency because there is no state," Hollande said as he addressed reporters in Pretoria alongside South African President Jacob Zuma.
"There is also an emergency at a regional level because there is a risk of spillover. We might witness religious conflict," he said, in comments translated from French.
There have already been sectarian clashes in the conflict that has driven more than 400,000 people from their homes, fleeing violence including murder and rape.
France has about 400 troops in the capital, Bangui, and sources have told Reuters their numbers could be increased to around 750.
However, Paris is reluctant to be left to deal with another African hotspot after it felt allies such as the United States were hesitant to help it halt a rebel advance by al Qaeda-linked insurgents in Mali earlier this year.
The Central African Republic is geographically at the centre of what some strategists have called an "arc of insecurity" of Islamist fighters that cuts from Kenya and Somalia in east Africa across to Mauritania in the west.
Hollande said there was need for African governments to develop a standby force to deal with conflicts as they arise.
The African Union has deployed about 2,500 troops. But its resources are limited, prompting Paris to seek a U.N. Security Council mandate that would turn the operation into a U.N. peacekeeping force ultimately supported by French troops.
Foreign Minister Laurent Fabius, who visited Bangui on Sunday, said the U.N. resolution was expected around December.
While South Africa's Zuma said he agreed intervention was needed, he stopped short of saying Pretoria would send more troops.
Pretoria's involvement in the Central African Republic is a sensitive issue after South Africa lost 14 soldiers in March clashes with rebels near Bangui, with the incident being seen as one of the major foreign policy blunders of Zuma's government.