The Productivity Commission is seeking feedback on how - and how far - to deepen economic integration with Australia.
Between the present situation, where there are few barriers to the movement of goods, people and capital between the two countries, and full political union lies what it calls economic union. That involves a common currency, common monetary and fiscal policy, and harmonised tax rates.
Among the questions the commission, along with its Australian counterpart, pose in a high-level issues paper just released are what the appropriate end-point to trans-tasman integration is, whether there are any thresholds which should not be crossed on the grounds they would compromise sovereignty, and what the advantages and disadvantages of a currency union with Australia would be.
There are potential benefits in avoiding the transaction costs associated with having separate currencies.
"On the other [hand], where business cycles and economic changes [such as the 'mining boom'] affect the two countries differently, there could be costs in not having independent exchange rates. The recent experience of countries in the Eurozone is instructive in this respect."