MELBOURNE (Reuters) - New Zealand Prime Minister Jacinda Ardern said on Saturday she will announce her new government on Monday after offering the Green Party two ministerial portfolios outside of cabinet as part of a proposed cooperation agreement. Ardern delivered earlier this month the biggest election victory for her centre-left Labour Party in half a century. Although she no longer needs support to govern, coalitions are the norm in New Zealand as parties look to build consensus. Under the agreement offered to the Green Party - one of Ardern government’s coalition partners prior to the election - the two portfolios would be held by the Green Party’s co-leaders.