Jacob Zuma, favourite to become South Africa's next president after April's polls, says he does not consider his newest opposition a major challenge.
He told the BBC he is not worried about the threat posed by the Congress of the People (Cope).
Cope is composed of dissidents from the ruling African National Congress (ANC), led by Mr Zuma.
But Cope leader Mosiuoa Lekota says that Mr Zuma is underestimating the "glaring failures" of the ANC.
Mr Lekota says his party will win about a quarter of the votes in the election and even suggested that Cope might form a coalition government with other opposition parties.
The emergence of Cope and the corruption charges faced by Mr Zuma make the 22 April elections the most keenly contested since the end of apartheid in 1994.
However, correspondents say the ANC is almost certain to retain its majority in parliament, leading to Mr Zuma becoming the next president.
"All elections are tough, no elections are easy," Mr Zuma told the BBC's Peter Biles.
But when questioned about Cope he added: "We don't see it as a major challenge."
"You cannot say this is a big challenge when there is no policy, no major, serious policy challenges to pose as an alternative to those of the ANC."
He is due to face renewed corruption charges in August. He repeated that he was innocent and would only step down if found guilty.
Mr Lekota, a former defence minister, formed Cope when President Thabo Mbeki stepped down last September as a result of a power struggle with Mr Zuma.
"I think he's underplaying the failures of the present government," Mr Lekota told the BBC in London.
Citing the optimism when President Nelson Mandela was first inaugurated as head of state in 1994, Mr Lekota said:
"The promises then put before the people have largely been frustrated."
Based on the results of by-elections since Cope was founded, he predicted the party would win at least 22% of the vote and win control of some provincial governments, either outright, or in coalition.
The Democratic Alliance is currently the largest opposition party in parliament but Mr Lekota clearly believes that after April's election it will take most anti-ANC votes, and become the official opposition.