Corruption Watch has expressed concern over South Africa dropping down the rankings of the latest Corruption Perceptions Index (CPI) released by Transparency International.

Corruption Watch's Phemelo Khaas said South Africa's score dropped from 45 in 2017 to 43 this year, and although it seems "a marginal shift" it should be of concern.

"This is of particular concern given that the CPI just released reflects the outcome of surveys conducted in 2016, prior to the dismissal (for the second time) of former finance minister Pravin Gordhan, action relating to the Public Protector's October 2016 State of Capture report, and the daily scandals and revelations of grand corruption that characterised 2017," Khaas said.

The index looks at the corruption perception of 180 countries and territories based on a scale of zero to 100, with zero being highly corrupt and 100 very clean.

At the top of the list are New Zealand, Denmark, Finland, Norway and Switzerland, while Somalia, South Sudan and Syria are perceived as the most corrupt.

"This year, the index found that more than two thirds of countries score below 50, and in this context, South Africa continues to be in the company of those countries in the world considered to have a serious corruption problem," said Khaas.

'Continued impunity' of its leaders

"As indicated above, the real spiral in the country began at the end of 2016, the year in which the survey was completed, when there was a marked escalation in revealing corruption, primarily through a robust civil society and media.

"The increased exposure of corrupt activities can be attributed to a more vocal and active citizenry, but despite these mounting calls for accountability, the lack of prosecution remains a major obstacle in the fight against corruption," Khaas said.

Khaas said the "continued impunity" of South Africa's leaders has ensured South Africa was not able to progress beyond the low- to mid-40s on the index since Corruption Watch was launched.

"This signals an alarming lack of progress in really improving our standing in a global context, in spite of ramped-up efforts to out the perpetrators of corruption," Khaas said.

"South Africa is ranked ninth in relation to other sub-Saharan African countries, and this year was overtaken by Senegal. Once again, Botswana topped the charts and the only newcomer in the top 10 this year is the Seychelles, with Ghana having conceded its position."

Khaas said although the ranking wasn't great, it shows that sound financial and judicial institutions protect the country against corruption.

"The real test, however, is in the success in bringing corrupt people to book, and the failure of the prosecutorial bodies to act independently and decisively on matters during this period. Until there is evidence of people not only losing their jobs, but doing jail time for their corrupt activities, the country will continue to be grouped among the most corrupt and unsavoury places in the world," Khaas said.