Crossbench senator Bob Day is attempting to delay the Federal Government's changes to voting laws, in a bid to prevent a double dissolution election.

Under the proposal by the Family First senator, a six-month review would be implemented that would take it past the election cut-off date.

The changes, already introduced into Parliament, are designed to make it harder for crossbenchers to get elected if they have a tiny proportion of the vote.

They are due to pass with the support of the Greens and Senator Nick Xenophon, but Senator Day, who was elected to the Senate in 2013 with just 2,757 first preference votes, told the ABC the changes should not be rushed through.

"This is the biggest change to our voting system in over 30 years and the Government is allowing one week to review it," the South Australian senator said.

"People make mistakes — especially in this place, in Parliament House — and there will definitely be unintended consequences."

His request has drawn criticism from Greens leader Richard Di Natale, who said it was based on self-interest.

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The Greens are likely to benefit from the changes, but Senator Di Natale denied any self-interest on his own behalf.

He said it was a matter of principle for voters to control where their vote ends up, and slammed the opposition from crossbenchers and Labor.

"There are people inside the Labor Party whose currency is doing these back-room deals," he said.

"That's who they wield their power and influence. They're the people fighting the hardest to keep the status quo."

Senator Di Natale said while he liked some crossbenchers, "for every Ricky Muir, there's a Steve Fielding, a Bob Day, a David Leyonhjelm who game the system".

Senator Leyonhjelm told Channel Nine this morning he would struggle to be re-elected under the new rules.

Meanwhile, outgoing Labor MP Gary Gray has told Parliament that reform would remain a critical issue.

Labor is opposed to the reforms and has done internal analysis on its impacts, but Mr Gray dismissed the figures as "nonsense".

He has told the Lower House that he favoured the reforms, but would not cross the floor to support the Government.

The Government has also abandoned its plans not to count Senate votes on election night.

It had initially planned to only release a figure of how many ballots have been cast, and count Senate votes later.

But it has now confirmed it will count Senate first preferences on election night in order to provide as transparent a result as possible.