By James Macharia
JOHANNESBURG (Reuters) - A majority of Africans say corruption has risen in the past 12 months and most governments are seen as failing to stop bribery and secret deals, an opinion poll by Transparency International showed on Tuesday.
South Africa was ranked the continent's most corrupt nation by respondents, followed by Ghana and Nigeria.
President Jacob Zuma of South Africa said in October the ruling party was losing membership before key local elections next year over perceptions it was "soft on corruption" and amid criticism and public marches led by opposition parties, unions and ordinary citizens.
The findings come at a time when public frustration is mounting across the world's poorest continent over the failure of authorities to fight corruption by prosecuting top officials accused of graft.
For the first time, the survey shows, people reported business executives as highly corrupt, ranking second to the police, who have regularly been ranked as most corrupt in previous surveys. Government and tax officials rank third and fourth respectively as the most corrupt groups.
Some 58 percent of Africans in the surveyed countries said corruption had increased over the past 12 months, showed the report entitled People and Corruption: Africa Survey 2015, which is part of Transparency's Global Corruption Barometer.
In 18 out of 28 countries surveyed, a majority of people said their government was doing badly at fighting corruption.
"It is time to say enough and unmask the corrupt," said Transparency International Chairman Jose Ugaz.
In Sierra Leone, Nigeria, Liberia and Ghana, respondents said the scale of corruption was on the rise, while citizens in Botswana, Burkina Faso, Lesotho and Senegal said graft was being addressed, the report said.
Three-quarters or more of respondents in South Africa, Ghana and Nigeria said corruption had risen, but in Burkina Faso, Cote D’Ivoire and Mali, less than one-third of respondents said graft had increased, the report said.
For its report, Transparency International partnered with Afrobarometer, which spoke to 43,143 respondents across 28 Sub-Saharan African countries between March 2014 and September 2015 to ask them about their experiences of corruption.
Across Africa, presidents are speaking against graft, but the report found that 64 percent think their governments are doing a poor job at fighting it. This suggests greater efforts need to be taken to clean up the public sector and to punish officials for their corrupt actions.
Nigeria's President Muhammadu Buhari has promised to "clean up" Africa's biggest economy, starting with the oil sector.
Kenyan President Uhuru Kenyatta reshuffled his cabinet last week following mounting public pressure after several ministers faced corruption allegations. This was just days ahead of a visit by Pope Francis, who urged Kenyans to shun corruption, saying it "is like sugar, sweet, we like, it's easy."
(Editing by Tom Heneghan)