Governments are not doing enough in the global fight against graft, anti-corruption watchdog Transparency International (TI) said Wednesday as it presented its annual corruption perceptions index.
Many nations have made no progress at all over the past six years, the group found.
"More corruption correlates with less respect for civil liberties, for rule of law, for access to justice," TI chair Delia Ferreira Rubio told AFP.
"The index reflects the relation between transparency and democracy."
Over the past six years, some countries such as Senegal, Ivory Coast and Britain have bolstered efforts to battle corruption, TI found.
Others have slipped lower in the NGO's worldwide ranking, including Syria -- whose civil war will enter its eighth year in March -- or Yemen, where fighting has raged for more than three years.
"Countries where rule of law is respected, freedom of expression is respected, freedom of the press is respected" topped in the rankings, Ferreira Rubio said.
New Zealand remained in first place, but Nordic countries again dominated the top of the table, including Denmark at second place, Finland and Norway tied for third with Switzerland, and Sweden in sixth alongside Singapore.
Canada and Britain were tied with Luxembourg and the Netherlands for eighth place, while Germany claimed 12th.
Somalia was the worst performer, ranking last among the 180 nations listed, below South Sudan, Syria, Afghanistan and Yemen.
TI's table is compiled by awarding countries a score of between one and 100, based on data from 12 international organisations including the World Bank, African Development Bank and the World Economic Forum.
TI managing director Patricia Moreira said that "no activist or reporter should have to fear for their lives when speaking out against corruption".
"Given current crackdowns on both civil society and the media worldwide, we need to do more to protect those who speak up."