A gold mining company says it took immediate action after safety officials issued a prohibition order at its Reefton mine on the West Coast.
A union representing mine workers has accused the firm of hypocrisy over safety.
OceanaGold told a select committee on Thursday legislation to improve mine safety in the wake of the Pike River disaster should not apply to mines that are above ground and are not coal mines.
Alan Clarence of the Engineering, Printing and Manufacturing Union says Oceana Gold told the committee it was squeaky clean, while knowing its Reefton mine has a prohibition notice in place. He said waste-tipping trucks were at serious risk of falling down a 50-metre cliff.
On Friday, OceanaGold said it was made aware two days earlier that aspects of its operating procedures for tipping waste rock in an area of the operation were not being consistently practised.
It said it acted immediately to address the issue and the gold mine is continuing to operate.