Turnbull throws down Senate gauntlet

TURNBULL SETS ELECTION FUSE

* PM gets vice-regal permission to recall parliament on April 18.

* Senate has three weeks to consider a government bill restoring the building and construction watchdog - dismantled by Labor - and another bill imposing higher penalties for union corruption.

* If the Senate rejects, amends or fails to pass the bills there will be a double-dissolution election on July 2.

* If the Senate passes the bills, there will be an election between August and October.

* Budget brought forward to May 3 to accommodate a double-dissolution election that needs to be called by May 11.