Twelve protesters had been occupying a mining site in Karangahake.
The High Court overturned its application to mine iron sands from the seabed.
RNG Minerals said it extracted gold worth $18 million.
The 48-hour strike could be the first of many by OceanaGold employees.
Opponents are calling it a "huge win for the oceans".
It promises to return one day for the bodies.
"It's that wall that’s stopping us from re-entering... I just want to tear it down myself."
Mining company OceanaGold has two drill rigs exploring the area.
It includes "thoughts and prayers" for the family of the would-be deceased.
"Recovery of the mine drift is technically feasible and the risks of harm can be managed and minimised."
A quadrillion tonnes of diamonds have been found.
New evidence inside the mine could spark a prosecution, Nigel Hampton QC says.
The minister says it's now just a question of working out the details.
He says much of the country's conservation land is just "scrubland" and could be mined not just for resources, but jobs.
A commissioner and top investigator have briefed the families - and won't rule out charges.
The Government said any economic benefit would not outweigh ecological damage.
A meeting held in Greymouth on Thursday came up with three re-entry options.
The material is used in smartphones, hybrid-vehicle batteries and military technology.