Joyce will be a different leader: Truss

Warren Truss has given the strongest indication his deputy Barnaby Joyce is likely to succeed him as federal Nationals leader.

Mr Truss says there is a strong record of deputies becoming leader in the country party.

However, the decision was not up to him, but the party room.

"I don't think it is appropriate for one leader to anoint another," Mr Truss told reporters in Canberra on Wednesday amid continuing speculation he will announce his retirement within weeks.

Mr Truss said Mr Joyce had enormous skills and abilities to become leader, but so too did other Nationals including Michael McCormack.

"He will be a different kind of leader than me but that is true of every leader that follows their predecessor."

Meanwhile, the junior coalition partner is also set to get an extra place when Malcolm Turnbull reshuffles his cabinet.

The prime minister had made it clear the issue would be addressed in a future reshuffle, Mr Truss said.

NATIONALS DEPUTIES WHO BECAME LEADER:

Doug Anthony (1971-1984)

Ian Sinclair (1984-1989)

John Anderson (1999-2005)

Mark Vaile (2005-2007)

Warren Truss (2007- )

* Terms as leader