Senate crossbenchers John Madigan and Nick Xenophon frustrated by Coalition's negotiating tactics

Two crossbench senators say they are becoming increasingly frustrated with the way they are being treated by the Federal Government.

Senator John Madigan, who today announced he was quitting the Democratic Labour Party over internal issues to serve as an independent, said the Coalition rammed through changes to the mining tax and superannuation without time for proper consideration of the legislation.

Independent senator Nick Xenophon said the Government is acting without integrity and is eroding trust, and that could lead to greater dysfunction in Parliament.

Senator Xenophon said some crossbenchers were not told about the deal to scrap the mining tax until shortly before it came to the Senate, giving them little time to consider the details.

"In terms of politics I guess it was masterful but in terms of democracy, it was a disgrace," he said.

"I will always negotiate in good faith with any of my parliamentary colleagues but the Government needs to understand that there is a justifiable degree of wariness there.

"This may have been good politics but in terms of what it means for the way the Parliament will work in the future, it will mean I'll be a little more wary."

He warns the Coalition that stitching up secret deals with the Palmer United Party (PUP) could ultimately backfire on the Government.

"I think that this will unravel sooner rather than later because this is not the way to run a legislative agenda," he said.

"If you increase the level of distrust with the crossbenchers then you really sow the seeds for a more dysfunctional Parliament."

Senator Madigan has similar frustrations.

"I'm not obstructionist, but I do believe in the Senate reviewing legislation," he said.

"Fair enough, the Government had amendments to the legislation.

"[But] to do them justice you've got to have time to look at them and there were several pages of them, but they didn't allow for that time."

Government urged to act 'with integrity and transparency'

Last-minute deals add to the difficulties crossbench senators already have with keeping across a wide range of complex bills before the chamber.

Senator Madigan said in the confusion of the mining tax machinations, he accidentally supported the Government guillotining debate on the deal.

"Inadvertently I voted for it and I sincerely regret that, I made a blue," he said.

There is no shortage of contentious legislation the Government needs to win crossbench support for — the GP co-payment and higher education changes among them.

Senator Xenophon said the Coalition should heed the advice of one of its own.

"In the words of their former Senate leader, Nick Minchin, who basically said in his final speech to the Senate that you need to behave with decency and integrity and if you do people over, expect the same thing to happen to you," he said.

"I think Nick Minchin's words sum it up pretty well and I think the Coalition needs to be very aware of what Nick Minchin said.

"That is the code by which to operate — with decency and integrity and transparency.

"I don't think the Government did that a few days ago."

The Senate voted to repeal the mining tax after the Government struck a deal with the PUP to keep the schoolkids bonus until after the next election.

But the agreement also further delays superannuation increases for Australian workers, putting them on hold until 2021.

See how the super changes affect you: