The fracturing of the Palmer United Party is causing a power shift in Parliament, crossbenchers say, with Nick Xenophon emerging as a power player to rival Clive Palmer.

As Tasmanian Senator Jacqui Lambie contemplated her likely split from PUP over the weekend, the government has already recalibrated its strategy in dealing with the crossbench.

Coalition Senate leader Eric Abetz has invited all crossbenchers to a briefing on Monday morning. The 15-minute session, to be conducted by Senator Abetz's senior aide Don Morris, will outline the government's legislative agenda for the final fortnight of Parliament.

In previous months, no official briefings have been provided, with the government's focus almost exclusively on winning the support of Mr Palmer who has been able to direct the bloc vote of his three senators and Motoring Enthusiast Ricky Muir.

But the participation of Senator Lambie and Senator Muir in the so-called "coalition of common sense" that overturned the government's financial advice regulations last week marked a redrawing of alliances and power relationships.