She will also pick up the extra duties of deputy, although Little said she would not fill the usual mould of deputy and would instead help him campaign.
That starts immediately - Ardern will accompany Little on a series of public meetings this week, including in Wellington, Hawke's Bay, and Auckland.
Little said Woods had performed well in climate change and Christchurch, and would also pick up Energy, Innovation and Science and Research and Development from Stuart Nash.
Nash had also been moved up into the top 12 which Little describes as his "front bench" and will take Economic Development as well as his Police and Forestry portfolios.
There is also a promotion for Te Tai Hauauru MP Adrian Rurawhe who gets bumped up into the shadow Cabinet while Tamaki Makaurau MP Peeni Henare will take over State Owned Enterprises.
Raymond Huo is set to return to Parliament soon to replace Ardern on the list and will do the Land Information portfolio.
That gives him some work in the area of foreign buyers - Land Information includes the Overseas Investment Office, as well as data collected on foreign buyers by the Government.
It is held by David Cunliffe, who is expected to leave Parliament next month to take up a new job.
Clark and Woods both entered Parliament in 2011 with Little.
Little said Clark had worked closely with King in health and he was confident he would do well.
"David's skills and experience will be invaluable in communicating to the electorate how Labour will fix the health system."
Little had invited King, a former Health Minister, to retain the portfolio and become a minister if Labour was in Government, but King decided to quit Parliament at the election instead.
King has moved out of the shadow cabinet but will take the State Services portfolio until the election.