Treasurer Scott Morrison expects the planned overhaul of the GST distribution system will be agreed upon in coming months.

Mr Morrison will ask a meeting of the nation’s treasurers in September to back a new “floor” of 70 cents in the dollar from 2022/23, rising to 75 cents from 2024/25.

He wants to lock the plan down in a permanent inter-governmental agreement and says discussions so far have been productive.

“I’m very confident we’ll be able to land that by the end of the year, if not sooner,” Mr Morrison told 6PR radio on Tuesday.

Federal opposition leader Bill Shorten said on the weekend the planned change should be legislated, urging the federal government to “make the floor the law”.

Mr Morrison told a business function in Perth on Monday that permanent inter-governmental agreements worked well, but he was “open to” legislation.

Deputy Premier Roger Cook said people just want the system to be fixed.

“West Australians are just heartily sick and tired of the debate,” he told reporters on Tuesday.