Voters could go to the polls later in the year under a new Senate voting system which ends backroom preference deals but favours major parties.
22 Feb 2016 - 11:09 AM  UPDATED 22 Feb 2016 - 7:44 PM

Changes to the way senators are elected will put power back into the hands of voters and end backroom preference deals, Prime Minister Malcolm Turnbull says.

The government is rushing legislation into parliament on Monday that will allow voters to cast preferences above the line on Senate ballot papers.

Voters now can only validly put a "1" in a box, with preferences flowing via a group voting ticket lodged by a candidate or party.

These preference flows are determined by deals done between parties and, in more recent times, so-called preference whisperers working with micro-parties.

Under the proposed system, which Mr Turnbull wants in place for the next election, voters will be able to cast preferences up to the number of Senate vacancies being filled in their state or territory.

"What these changes will do, what they seek to do, is to ensure that Australian voters determine where their Senate votes go," Mr Turnbull told reporters in Canberra.

The Greens have given their in-principle support but are waiting to see the details.

Labor senator Sam Dastyari described it as "complete rort".

"The Senate is a better place when more diverse voices are being heard," he said.

Mr Turnbull said the 2013 Senate election result had been widely criticised because some senators won their seats with less than one per cent of the primary vote.

"The alternative is that a political party trades those (preference) votes away in secret without actually reflecting the true intention of the voter," he said.

Liberal Democrats senator David Leyonhjelm told AAP the change was undemocratic and was being done to favour the major parties.

"It will also ensure the Senate is permanently gridlocked (between the coalition, Greens and Labor)," he said.

Asked whether it could lead to angry crossbenchers effectively boycotting all government bills, Mr Turnbull said: "I would hope that Senate crossbenchers will vote on legislation on its merits and without regard to whatever they may perceive to be their personal electoral agenda."

Election analyst Antony Green said the coalition would find it easier to win three seats in each state at a half-Senate election while Labor would ordinarily win two and battle with the Greens for the sixth seat.

Palmer United Party senator Dio Wang said the new system was merely "political tactics" by the government and it would have been better to limit preferences "below the line".

Independent senator Nick Xenophon said it would bring an end to "bizarre" preference deals, giving the example of how Labor preferences saw the election of Family First's Bob Day in South Australia.

"It will give minor parties a fighting chance," he said.

The introduction of the laws has increased the prospect of Mr Turnbull calling an early double-dissolution election.