Transparency Solomon Islands says the country cannot afford to increase the number of seats in the national parliament.
There are currently 50 seats but a new bill would allow for an increase to a maximum of 70 seats, after the government was initially looking at an increase by 12 MPs.
The NGO is warning against the proposed Constitutional Amendment Bill tabled in parliament this week by the Prime Minister Derek Sikua.
He says submissions show a desire for splitting large constituencies to cater for different language groups.
But Transparency's chairman Bob Pollard says such an increase cannot be justified in a country of half a million.
"Simply, the country is over-governed. The number of elected MPs per persons is unbelievable. The country simply cannot afford to keep on increasing the number of elected leaders who will expect to be paid a salary and all the entitlements that go along with it. So it's not a good move for the country."