The head of New Caledonia's Goro Nickel company, Phil du Toit, says if the planned waste pipe cannot be used the nickel plant won't be able to operate.
Construction of the pipe is on hold amid opposition by some locals and environmentalists who fear the effluent will pollute the waters considered to be turned into Unesco World Heritage site.
In an interview with the Nouvelles Caledoniennes newspaper, Mr du Toit says the pipe is the best solution and will not damage the environment.
He says the company has a dialogue with those opposed to the project and says the pipe is scheduled to be tested some time between May and August.
Mr du Toit says the investors into the five billion US dollar project have been surprsied and disappointed over the sudden objections to the pipe.
He says Goro Nickel's construction phase will yield hundreds of millions of dollars in investments into the local economy.