Parliament returns for four-day sitting

THE WEEK AHEAD IN PARLIAMENT

* House of Representatives is sitting over four days.

* MPs will consider laws to make migrants wait longer for welfare payments, and cracking down on revenge porn.

* Nationals party room will vote on Monday morning on a new leader to replace Barnaby Joyce.

* No Senate sitting, but estimates hearings.

* Question Time in the House is expected to focus on Malcolm Turnbull's handling of the Joyce scandal and the secret coalition agreement.

* Two state elections in Tasmania and South Australia and the Batman by-election in Victoria will put issues in these three states in the parliamentary spotlight.

* The government has threatened to refer Labor MP Susan Lamb to the High Court over her UK citizenship, but is yet to act on it.

* With the exit of George Brandis, Mathias Cormann will fend off Senate estimates questions from Labor's chief inquisitor Penny Wong.

* Key topics for Senate estimates to include: Parliament House's security upgrade; MP expenses; the rollout of the new Home Affairs portfolio; the under-spend on roads; energy prices; Snowy Hydro 2.0; the Murray Darling Basin Plan; moving government agencies out of Canberra; Medicare; defence operations and spending; the economy and budget; and welfare reform.

* Expert pot-stirrer, Nationals MP George Christensen, will seek parliament's support for a motion in favour of the Adani coal mine in Queensland, which he says will create 15,000 jobs and improve the lives of Indians.