Political parties taking part in the coalition negotiations after the election asked for information on everything from the cost of NZ First's wish for an Auckland to Northport rail to the Green Party's request to build a new refugee resettlement centre outside Auckland and on the costs of immediately halting all permits for new coal mines, offshore oil drilling and fracking.

The State Services Commission has released the information it provided to the parties during the negotiations.

Those negotiations took place over a fortnight after the final election results were known between Labour and the Greens, Labour and NZ First and National and NZ First.

NZ First eventually opted to go into coalition with Labour with the Green Party as a confidence and supply support partner.

Parties involved in such negotiations over policies can seek information from officials to help the process and the release shows the Green Party made most use of this.

The information reveals some of the topics that were subjects of negotiations but did not make it into the final agreements – such as the Green Party's desire to lift the refugee quota to 4000 and build a new refugee resettlement centre, and any work that had been done on a nitrogen pollution charge for agriculture and water charges.

The latter was both Green Party and Labour Party policy, but Labour abandoned it after NZ First objected.

The Greens also sought information on measuring "natural capital" and stocks such as fisheries, soil and indigenous species in the national accounts.

The release shows Labour asked for an estimate on the cost of NZ First's wish to connect Northport to Auckland by rail, including upgrading the current line as well as the new connection to Northport.

Labour also sought information on the cost to increase the minimum wage to $20 an hour by 2020 – one of the policies that was adopted by the new government.

Labour also asked for any estimates of the expected cost to the next government of any pending collective agreement negotiations and equal pay settlements that had already been lodged, or where a group had indicated it would do so.

The only request from National was for a briefing from immigration officials for its talks with NZ First on the matter, "in particular the interface between overall residents numbers and the skilled migrant category".

State Services Commissioner Peter Hughes said he had advised the parties from the outset that the information they were furnished would be released publicly. He said SSC's focus was on ensuring the political neutrality of the public service while ensuring parties received the required information.