The Berlin-based group's survey of 1,000 people in Germany found that while individual bribery was rare, seven out of 10 respondents felt that corruption had risen in the past three years.
“We view this figure as a warning signal that political parties should wake up,” the group's chairwoman, Edda Müller, told broadcaster ARD.
The Corruption Barometer 2010 found that just two percent of Germans said they had paid a bribe in the past year, compared with a global average of 25 percent. But respondents were clearly worried their politicians could be bought by lobbyists.
Specifically, a recent cut in sales tax for hotel stays and the donations by the hotel industry to the pro-business Free Democratic Party, the junior members of the ruling coalition, were of concern, Müller said. The lifetime extension of Germany's nuclear power plants and the might of the atomic energy lobby also appeared to affect respondents' thinking.
“Parties are getting dangerously closer to gambling away the trust and the support of their voters,” Müller warned.
Ultimately there was little difference between certain forms of lobbying and corruption, she said.