Nationals cross the floor on effects test

Newly-installed prime minister Malcolm Turnbull has faced his first revolt with three Nationals crossing the floor of the Senate to vote against the government.

Bridget McKenzie, John Williams and Matt Canavan backed a Greens motion calling for a so-called effects test on market power to be included in competition policy.

The measure was earlier taken up with Mr Turnbull by Nationals leader Warren Truss as part of their discussions about a new coalition agreement.