The government is set to secure reforms to the Senate voting system that will squeeze out “micro”-players.

Immediately after the changes were announced by Prime Minister Malcolm Turnbull and Special Minister of State Mathias Cormann, the Greens welcomed the move and called on the ALP to support it.

While the Greens said they would scrutinise the legislation, which was introduced in the House of Representatives immediately after the announcement, they have had extensive negotiations with the government. Support from the Greens is all that is needed to get the measures through the Senate.

The changes would bring in optional preferential voting “above the line”, replacing the present group voting tickets. Voters would be advised to number at least six boxes in order of choice. But their vote would still be valid if they numbered only one box.

At present, people just mark one box but have no control over their preferences. Complicated deals over preferences have meant the election of candidates on tiny votes.

Almost all voters vote above the line.

In relation to below-the-line voting, the government proposes to reduce the number of informal votes by increasing the number of mistakes allowed from three to five, as long as 90% of the voting paper is filled in correctly.

Group and individual voting tickets will be abolished.

A restriction will be introduced to prevent individuals holding relevant official positions in multiple parties.

The changes also allow parties, if they wish, to have their logos on the ballot paper, to reduce confusion. At the last election the Liberals complained that many of their voters thought the Liberal Democratic Party (LDP) was the Liberal Party. The LDP got senator David Leyonhjelm elected in NSW.

Turnbull said there had been much criticism of the last Senate election. People were astonished to see senators elected on very small votes. Under the reforms every Australian who voted in the Senate “will determine where their vote goes. And that’s democracy”, he said.

If there is a double dissolution all or almost all micro-players would be immediately out. A normal election would make it nearly impossible for new micro-players, but the several elected in 2013 would still have more than half of their term remaining.

Amid speculation about a double dissolution, Turnbull said “nothing has changed”. He was working on the assumption that the election would be held at the normal time – which was August, September or October.

Turnbull said the government did not have a view on who would be electoral winners out of the change. He pointed out that the reform was recommended unanimously by the Joint Standing Committee on Electoral Matters.

That committee will now scrutinise the legislation, which the government wants passed by the time parliament rises for the autumn recess in mid-March. It will take the Electoral Commission about three months to make the necessary changes, which means they could be ready for either a normal election or a July double dissolution.

Greens leader Richard Di Natale said the Greens had been putting forward legislation over 12 years for Senate voting reform that ended backroom preference deals and put power back into the hands of voters.

“The only people who support the current system are the faceless men and factional operators who can wield power and influence in back rooms,” he said.

Independent senator Nick Xenophon, who won almost two quotas at the last election, supports Senate voting reform.

Labor, despite supporting reforms on the parliamentary committee, has since become sharply divided. Some factional heavyweights strongly oppose them, believing they would work to the Coalition’s advantage. Opposition Leader Bill Shorten reserved Labor’s position.

Motoring Enthusiast Party Senator Ricky Muir, elected in 2013 on about 0.5% of the Victorian Senate vote, tweeted his disapproval of Turnbull’s move.