The harmonisation of banking regulations and a common currency are talking points in an issues paper published by the Productivity Commissions of both Australia and New Zealand yesterday.The release of the joint study does not appear to have received much fanfare in spite of the notional sponsorship of the exercise by the prime ministers of each nation.The broad remit of the two commissions is "to conduct a joint scoping study on strengthening trans-Tasman economic relations", according to the overview published in the issues paper."The approach to this scoping study will be to seek out a reform agenda that would improve the welfare of both the Australian and New Zealand communities," the issues paper declares.One area of potential reform, banking regulation, has been rather off the agenda than on in recent years, with the last such effort petering out in the mid-2000s.The issue paper cites the limited goals of the Trans-Tasman Council on Banking Supervision that was "established to promote a joint approach to banking supervision, so as to deliver a seamless regulatory environment in banking services. "The Council has not aimed to align regulatory objectives, rules and approaches but rather allow the two countries' regulatory frameworks and regulators to operate with fewer points of potential friction."The issues paper cites complaints from ANZ (that are likely to be shared by other major banks) over "material differences between the Australian and New Zealand regulatory environments that require operations to be duplicated and extra expenses to be incurred."The two commissions also venture into the even more (politically) difficult terrain of a common currency.The discussion on this point is muted."On one hand, there are potential benefits in avoiding the transaction costs associated with having separate currencies. "On the other, 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."