The EPA released 3 reports on the NZETS recently http://www.epa.govt.nz/e-m-t/reports/ets_reports/annual/Pages/default.aspx
Of 45.5 million tonnes or emissions units surrendered for the 2013 compliance year, only 227,000 were NZUs. The balance were UN offsets predominantly ERUs. As of 1 July 2014 there were some 140 million NZUs sitting in private accounts.
The surrender of 45.5 million in 2013 was dominated by the forestry sector with foresters opting out of the NZETS and deforestation accounting for nearly 27m of the 45.5m.
In 2014 the picture is likely to change with a budget rule outlawing the use of non NZU for forest owners to exit the scheme or deforest. Forest-owner have correspondingly become unwilling to part with their NZU when they are now required to replace like with like. For May 2015 total surrender will also be a lot lower – perhaps < 20 million. Emitters retain the right to use ERU (and CER) right up until mid 2015.