Following national power shortages in 2001 and 2003 due to low hydro lake levels, the New Zealand government commissioned Contact Energy to build reserve generation on the Whirinaki site. This plant was intended to be a generator of last resort, providing back up generation when needed, such as during times of low hydro lake levels. The power station cost $150 million.

The diesel powered power station was opened in 2004, and comprises three Pratt & Whitney twinpacs, each with two FT8 gas turbines. Designed to be a standby power station, it has a total capacity of 155MW. The power station is maintained and operated by Contact Energy and it is state owned.

The Whirinaki Power Station sound wall was designed to block the sound produced by the power plant from neighbouring properties. The sound wall was 7m high and used 150mm Hebel Supercrete Sound Barriers.