PM not dumb on Senate: Labor ex-MP

A retired Labor MP says Malcolm Turnbull is "not ... quite as dumb as he looks" on changes to Senate voting and for calling a double-dissolution election.

Former minister Alan Griffin, who retired at the July 2 poll after 23 years in parliament, writes in The Australian on Tuesday that had nothing changed and had a regular election been called, the Senate crossbench would probably now be 14-strong.

The prime minister has been criticised in some quarters because the Senate crossbench swelled from eight to 11 at the federal election, but Mr Griffin says the large vote for minor parties and independents means a "fractious and contrary Senate looks likely to remain a fixture of our political landscape for many years to come".