Roger Cook has been named as WA's Health Minister and deputy premier in Mark McGowan's newly elected Labor government and has had mental health added back to his portfolio responsibilities.

Mr Cook has acted in the role of shadow minister for health since his election to state parliament in 2008 and proved a dogged pursuer of former health minister Kim Hames over the Liberal government's perceived failings in health, particularly the commissioning and opening of Fiona Stanley Hospital and its IT woes.