Prime Minister Jacinda Ardern announces extra duties for Winston Peters and Shane Jones

The Disarmament and Arms Control portfolio has been revived and added to the responsibilities of Foreign Minister Winston Peters. Photo / Mark Mitchell

Prime Minister Jacinda Ardern has announced some changes to Cabinet workload including giving Shane Jones extra duties to help New Zealand First leader Winston Peters as State Owned Enterprises Minister.

Jones, a minister for New Zealand First, is yet to receive his formal delegation of duties but it will not have anything to do with Air New Zealand, whom he recently criticised over closure of regional routes.

The sole minister with responsibility for Air NZ is Finance Minister Grant Robertson.

Ardern has also given Meka Whaitiri new responsibilities in forestry to help Jones with his tree planting programme.

And she has also changed one of the titles of Agriculture Minister Damien O'Connor to give him greater status when he is acting in his trade capacity overseas.

Jones will become Associate Minister for State Owned Enterprises.

It is not yet clear what delegation he will receive from Peters, who is also Deputy Prime Minister and Foreign Minister,

But the state-owned or partly state-owned companies for which Peters has oversight are: Airways Corporation, AsureQuality, KiwiRail, Kordia, Landcorp, the Meteorological Service, NZ Post (including Kiwibank), Quotable Value, Transpower, Genesis Energy, Meridian Energy, Mercury NZ, Christchurch Airport, Dunedin Airport, Hawke's Bay Airport, and Crown Infrastructure Partners.

He also has a shareholding in the residual companies of Solid Energy, NZ Railways Corp, ECNZ and Crown Asset Management.

Peters travels a lot as Foreign Minister and is due to take over as Prime Minister for six weeks from Ardern from mid June when she is due to have her baby.

Ardern said Jones would bring the SOE portfolio into alignment with his other ministerial responsibilities for Infrastructure and Regional Economic Development.

Whaitiri has been appointed Associate Minister of Forestry to help Jones acquire land on which to plant the promised one billion trees over 10 years – much of which may be on Maori-owned land.

O'Connor's title in trade has been changed from Associate Minister of Trade and Export Growth to Minister of State for Trade and Export Growth, which is designed to give him greater status when he is working overseas.

"No material change has been made to the portfolio responsibilities in this area, with Hon David Parker retaining principal responsibility for Trade and Export Growth matters," Ardern said.

"The title change will better signal to Hon Damien O'Connor's international counterparts the extent of his authority in international negotiations."

In a previously announced move, Peters will also become Minister of Disarmament and Arms Control, but Fletcher Tabuteau, who is already Peters' Under-secretary in Foreign Affairs, will become Peters' Under-secretary in Arms and Disarmament.

The last National Government appointed one minister of Disarmament and Arms Control, Dame Georgina te Heuheu, but then absorbed into the responsibilities of the Foreign Minister.

Ardern said the decision to reinstate Disarmament and Arms Control as a separate portfolio was an acknowledgement of the emphasis the Government places on New Zealand's anti-nuclear stance "and the role New Zealand must play, now and into the future".