Crossbench senator Glenn Lazarus has hit out at Malcolm Turnbull's "nasty" Government, saying he will snub a dinner invite to The Lodge in protest against Senate reforms aimed at disenfranchising the "common man".

Key points: A number of Senators reject PM's dinner invitation in protest over Senate voting changes

A number of Senators reject PM's dinner invitation in protest over Senate voting changes Senator Glenn Lazarus says changes will advance major parties

Senator Glenn Lazarus says changes will advance major parties Senator Nick Xenophon supports voting changes saying current system is "broken"

Senator Nick Xenophon supports voting changes saying current system is "broken" Voting changes due to pass with support of the Greens and Senator Xenophon

Senator Lazarus is among a group of crossbench senators who said they had been invited to dine with Mr Turnbull on Thursday.

The invitation had been extended before this week, when Mr Turnbull and Special Minister of State Mathias Cormann unveiled plans to overhaul the way Senators are elected.

Senator Lazarus today confirmed he cancelled his attendance, while Family First Senator Bob Day was "reconsidering his invitation".

The rugby league great told the ABC the proposed changes for electing senators would result in the Coalition being "able to ram through as much legislation as they want".

He said the changes would advantage the major parties and the voters would lose people who, like him, stood up for "the common man".

"The crossbench is a really diverse cross section of community," he said.

"We have people that come from very different backgrounds and I think that we've done a wonderful job in keeping this very nasty government accountable."

Senator Lazarus was elected on fewer than 7,000 first preference votes — and around 251,000 on the Palmer United Party (PUP) ticket — backed by PUP's multi-million-dollar electoral campaign.

He has since left the party.

Announcing the reform yesterday, Mr Turnbull said the legislation included the option of preferential voting above the line, meaning that voters could number up to six boxes and have their vote counted as formal.

The legislation will also propose:

Reducing the number of informal votes when voting below the line by increasing the number of allowable "mistakes" from three to five

Reducing the number of informal votes when voting below the line by increasing the number of allowable "mistakes" from three to five The abolition of group and individual voting tickets

The abolition of group and individual voting tickets Allowing political parties (at their discretion) to have their logo included on the ballot paper

Independent Senator Nick Xenophon came out in support of the proposals, saying no-one should be "preference whispering or [making] back-room deals".

Senator Xenophon, who negotiated with the Coalition on the reforms, told the ABC the proposal would give the power back to the people.

"This should be up to the voters. The current system is broken," he said.

"[It's] a system where the will of the people isn't appropriately reflected in the final composition of the Senate, a system where you can preference deals done."

Proposal set to pass despite opposition

The federal shadow cabinet will formally oppose the proposed changes, though they are due to pass with the support of the Greens and Senator Xenophon.

Shadow Treasurer Chris Bowen said that his "alarm bells ring" when the Coalition and the Greens do a deal.

His colleague Nick Champion described it as a "dirty deal done between the Liberals and the Greens, behind closed doors".

Mr Champion said progressive voters should be concerned about the potential for "nasty policies" to be passed.

"If you're relying on the Senate to knock back those policies, you would look aghast at what the Greens and what the Senate independents have done and what the Liberal Party have done in this deal," he said.

"It is an attempt to gerrymander the Senate and it will hand the Coalition control for the better part of two decades."

But outgoing Labor MP Gary Gray said there was need for reform.

The West Australian politician said the system "needs to be fixed" in a weekend opinion column published by the Weekend West.

Written before the details of the proposal were announced, Mr Gray said the system was being manipulated and "has begun to create unintended outcomes".

"Because of the ability to manipulate the current system, the present Senate voting process now fails this test," he wrote.