In its new Corruption Perception Index 2017, the NGO found that many countries are making little or no progress in ending corruption, with more than two-thirds of countries analysed scoring below 50 out of 100.

The index ranks 18 countries and territories by their perceived levels of public sector corruption, according to experts and businesspeople, using a scale of 0-100, where 0 is highly corrupt and 100 is very clean.

The NGO said that several countries had significantly improve their score over the last six years, including Côte d’Ivoire, Senegal and the United Kingdom, while a number of countries declined, including Syria, Yemen and Australia.

In the 2017 index, New Zealand and Denmark were ranked at the top with scores of 89 and 88 respectively.

Syria, South Sudan and Somalia ranked lowest with scores of 14, 12 and 9 respectively.

The best performing region was found to be Western Europe with an average score of 66, while the worst regions for corruption performance were Sub-Saharan Africa, with an average score of 32, and Eastern Europe and Central Asia, with 34 as the average score.

The analysis from Transparency International also found the crackdowns on NGOs and media were associated with higher levels of corruption.

"CPI results correlate with the attacks on press freedom and the reduction of space for civil society organisations,” said Delia Ferreira Rubio, chair of Transparency International.

“High levels of corruption also correlate with weak rule of law, lack of access to information, governmental control over social media and reduced citizens’ participation. In fact, what is at stake is the very essence of democracy and freedom.”

A survey found last month that efforts to make budgets more transparent stalled for the first in a decade, weakening trust in governments and increasing inequality.