On 26 April 1990, GM's New Zealand subsidiary Holden New Zealand announced that production at the assembly plant based in Trentham would be phased out and vehicles would be imported duty-free—this came after the 1984 closure of the Petone assembly line due to low output volumes. During the 1990s, Holden, other Australian automakers and trade unions pressured the Australian Government to halt the lowering of car import tariffs. By 1997, the federal government had already cut tariffs to 22.5 percent, from 57.5 percent ten years earlier; by 2000, a plan was formulated to reduce the tariffs to 15 percent. Holden was critical, saying that Australia's population was not large enough, and that the changes could tarnish the local industry.