The group, Forum Solomon Islands International says the attorney general has agreed to take legal action over the recent fourfold increase to MPs' entitlements.
Last month, the Parliamentary Entitlements Commission approved an increase from 14,000 US dollars to 56,000 dollars for parliamentarians finishing their four-year term.
The government must secure 2.8 million US dollars to meet the obligation at the time of next year's general election and the Forum is not alone in contending that is something the economy can ill afford.
The group's chief executive Benjamin Afuga says in the first instance the attorney general will write to the commission seeking an explanation for the increase.
"He will give them 14 days and he will ask them to revoke their decision. If not then he has told us that he will take up the challenge. There has already been a case in 2009 challenging a bad decision and the High Court has overturned the decision."
Benjamin Afuga says there was no consultation over the increase and the commission is obliged to explain it.