Mr Shaw will take on the climate change portfolio, while co-leader Metiria Turei will be responsible for inequality issues.
Mr Shaw will take the economic development role off his predecessor, Russel Norman, who will instead be responsible for trade and national security issues.
The party is also placing greater emphasis on housing and primary industries by allocating those portfolios to more senior MPs.
Mrs Turei will be responsible for housing, and fourth-ranked list MP Eugenie Sage will take over primary industries job from 14th-ranked MP Steffan Browning.
Explaining the change, Mr Shaw said: "The primary industries are a core part of the New Zealand economy, and provide some of the most exciting opportunities to transition our economy into a smarter, cleaner future."
Julie Anne Genter will take over the finance portfolio, which was previously held by Dr Norman.
PORTFOLIO LIST
Metiria Turei: Inequality, Building and Housing (inc. Social Housing, HNZ), Maori Affairs
James Shaw: Climate Change, Economic Development
Russel Norman: Trade, Justice (electoral), National Intelligence and Security (inc. NZSIS, GCSB)
Kevin Hague: Health (including ACC, Sport & Recreation), Conservation, Rainbow Issues
Eugenie Sage: Environment, Primary Industries, Land Information, Canterbury Earthquake Recovery, Earthquake Commission
Gareth Hughes: Energy and Resources, Tertiary Education, Skills and Employment, Science and Innovation, ICT, Broadcasting, Wellington Issues
Catherine Delahunty: Education (including Novopay), Water, Human Rights, Te Tiriti o Waitangi
Kennedy Graham: Foreign Affairs (including Defence, Disarmament, Customs), Veterans Affairs, Senior Citizens
Julie Genter: Finance (including Revenue, SOEs), Transport, Youth
Mojo Mathers: Commerce and Consumer Affairs (including Regulatory Reform), Disability Issues, Animal Welfare
Jan Logie: Social Development (including Women, Community and Voluntary Sector), State Services, Local Government (including Civil Defence), Rainbow Issues
Dave Clendon: Tourism, Small Business, Criminal Justice (including Courts, Corrections, Police), Musterer
Denise Roche: Workplace Relations and Safety, Waste, Immigration, Pacific Peoples, Ethnic Affairs, Internal Affairs (including Statistics, Arts Culture and Heritage, Ministerial Services, Racing, Gambling), Auckland Issues
Steffan Browning: Organics, GE, Biosecurity, Pesticides, Food Safety
- By Isaac Davison of the New Zealand Herald
