According to TI Slovenia, the country's score is bellow the EU and OECD averages of 64 and 68 points, respectively.
Presenting the survey, the NGO pointed to the absence of any systemic measures to make the fight against corruption in Slovenia more efficient.
"We are still waiting for the passage of the changes to the law on integrity and the prevention of corruption, and we are lagging behind reform-wise in other areas as well," said Alma Sedlar, the head of TI Slovenia.
She said that measures were being introduced too slowly and that Slovenia had also not implemented the EU directive on protection of whistle-blowers yet.
In this year's survey, TI focussed on political integrity and its impact on corruption in the world. An analysis of results has shown that the countries in which the financing of election campaigns is not transparent rank lower.
Sedlar stressed that TI Slovenia had warned of corruption risks in the financing of parties and campaigns years ago but nothing had been done.
"It is also worrying that this government continues to violate the resolution on legislative regulation, which limits the inclusion of the public in decision-making," she said.
TI Slovenia has been promoting political integrity with its Integrity Watch campaign, as part of which a publicly accessible interactive on-line base will be created based on the data available.
Thus, TI Slovenia wants to boost the oversight of the civil society over the areas with substantial corruption risks.
Sedlar said that in recent years several projects aimed at boosting political integrity such as an ethics code for MPs had come to standstill.
She also pointed to warnings from international organisations regarding pressure on judiciary.
As for lobbying contacts, Slovenia's Commission for Corruption Prevention has found that nine years since the implementation of the relevant law, the legal provisions have still not been properly implemented in practice.
The corruption watchdog commented on the CPI rankings today by saying it was not happy with Slovenia's ranking bellow the EU average.
No progress can be expected without major systemic changes and raising of political culture, it added.
The commission stressed that its findings were often ignored and the perpetrators went unpunished. This is why a mechanism should be introduced envisaging sanctions for elected public officials, it said.
The commission also pointed to the lack of legal basis for its operations. "Six years have passed since very clear and loud warnings that the systemic framework for the functioning of the commission is not appropriate. And in these six years, politicians did noting to improve it."
There are no major changes in the bottom or the top of the CPI rankings. As many as two-thirds of the countries scored less than 50 points and the average score is 43.
The list is topped by New Zealand and Denmark, which scored 87 points each, followed by Finland with one point less. Somalia (9 points), South Sudan (12 points) and Syria (13 points) are at the very bottom.
TI assessed that Belarus and Myanmar (14 points each) made the most progress in the last year, while the situation in Saint Lucia deteriorated the most, with its score dropping by 16 points to 55.
Slovenia's score matches that of Brunei Darussalam, Israel and Lithuania, which also got 60 points. The four are preceded by South Korea (59 points) and followed by Botswana (61 points).