The Papua New Guinea chapter of Transparency International is concerned that the huge support for the new National Alliance-led government may render parliament ineffectual.
The coalition formed by Sir Michael Somare includes 86 MPs from the 109-member house.
The TI secretary Richard Kassman, says a positive is the quality of the 23 opposition MPs, led by two former Prime Ministers Sir Julius Chan, Sir Mekere Morauta, and a former Treasurer, Bart Philemon.
But he says the fear is the executive will have too much control and can use Parliament as a rubber stamp.
"And those sheer numbers can gag debate on key issues so that is definitely a concerned. We are hoping in terms of what comes from the Opposition, the sort of research and commentary from the Opposition will certainly be of a higher quality this time around than in the past."