The 35 year old, who joined Wasps, is one of five players to have signed new, undisclosed-length contracts.
Gopperth, who left New Zealand in 2009, was initially ruled out for the season with an anterior cruciate ligament injury in August.
But he is now expected to make it back before the season ends in May.
Wasps are fourth in the Premiership table following last weekend's 24-14 loss at home to Bath.
