Natural gas customers on the Isle of Man could see their bills reduced by up to 12.6% if a new voluntary regulatory agreement is approved, the government has said.
Infrastructure Minister Ray Harmer said the proposals would introduce "fairer and more reasonable pricing".
The current agreement with Manx Gas, which was introduced in January 2015, sparked public protests.
Campaigner Barry Murphy said the proposals were "incomplete".
In February 2019, a review of the current arrangements concluded gas profits were too high.
Under the changes, which would be in place for 10 years, profits would be capped at 6.99%, down from 9.99%.
A review of government charges for the island's gas extension project could see a further reduction of up to 5.2% for natural gas customers as any reduction would be passed on.
The agreement, which would apply to all domestic customers and businesses using 12,000 or less kilowatt-hour (kWh) each year would be backdated to January 2020.
'More to give'
Mr Murphy, who has campaigned for a 20% reduction in bills, said the proposed reduction was "not very good" for customers in the long run.
There was "a lot more to give" and the government should "go back and look at the numbers better", he said.
"We're not looking for a short-term fix, and at the end of this I don't want to be grateful for anything, I'm only asking for what I'm entitled to."
Mr Harmer said he was "pleased that we have been able to progress negotiations" to reach "fairer and more reasonable pricing" for gas customers.
If Tynwald approves the overview, a finalised agreement will be brought back for debate in October.
If that does not happen, the government has said it will follow the "legislative route" to introduce regulation.
A 2,200 signature petition calling for an independent regulator will be presented to Tynwald members ahead of the debate.