The Solomon Islands leadership code commission says its work on investigating alleged misuse of government funds has been made difficult.
The commission has called off a probe into the payments made from the prime minister's discretionary fund between 2002 and 2003.
Its secretary, Florence Naesol, says more than a year of work was suspended because they couldn't prove any mistakes had been made because there were no guidelines for the fund.
"The discretionary fund that the PM has, doesn't have any criteria so it is quite difficult because you don't have anything there to investigate the way the PM handles that fund."
The commission is calling for MPs to pass legislation to control the prime minister's fund, which the Solomon Islands Development Trust says cannot simply be a slush account.