Support tumbles for rival to South Africa's ANC

* Support for COPE at 2.2 percent, down from 7.42 percent in April

* Needs to address leadership uncertainty

By Agnieszka Flak

JOHANNESBURG, Dec 16 (Reuters) - Support for a South African opposition party formed by defectors from the ruling African National Congress has slumped since the April election due to internal leadership battles, a poll showed on Wednesday.

Only 2.2 percent of eligible voters would back the Congress of the People (COPE), set up by loyalists of ousted President Thabo Mbeki in what was seen as the biggest challenge to the ruling party since apartheid ended in 1994.

COPE got over 7 percent of the vote in the election, giving it 30 seats in the 400-member parliament. But it did little to dent support for now President Jacob Zuma with its efforts to win over voters tired of scandals around him.

"The emergence of COPE has not been without controversy and several leadership struggles crippled the party, both before and after the general election in April 2009," said Ipsos Markinor, which carried out the poll.

It said said COPE might still turn things around, with 8 percent of those polled saying they would "perhaps vote" for the party.

Ipsos Markinor said the party's support was concentrated in the Gauteng province, South Africa's economic hub.