Opposition has centred on Māori water rights and the size of the new plant which will enable 1 million cubic metres of water to be taken each year.
Robertson said the majority of his staff affiliate to Ngati Awa and they have found it extremely hard to balance their loyalties to the iwi and their jobs.
"They've been accused of being disloyal and selling out by their family and that's been really hard for them to bear," he said.
"We also had a man come in here and threaten to blow us up for taking the water. He was very aggressive and for the mainly female staff working at the time it was very frightening."
Since the incident, the company has had to install security cameras to ensure the safety of its staff.
Creswell managing director Michael Gleissner said it had been an "extremely tough" time for the company.
"Staff are worrying about their jobs, they're worrying about the outcome of the court case and keep asking when the expansion will be happening," he said.
"When it does happen, staff will be provided more training, they will be doing less physical roles, they will be upskilled and with that, too, comes better wages and opportunities."
Gleissner said the artesian water is usually sold to high-end restaurants and hotels. However, as tourists have dried up, so too has their need for the water.
Thanks to Creswell's connection with overseas markets, it was able to diversify and has begun exporting to South Korea. Previously the water had only been exported sporadically. This, coupled with the wage subsidy, has kept the company going.
The High Court decision is expected before Christmas and Gleissner is confident it will be in the company's favour – just like the Environment Court decision. When it does, Gleissner said he is "shovel ready" and will begin construction just about immediately.
He estimates the construction will employ 170 people straightaway and will lead to 60 full-time well-paid jobs at the plant. The plant will export mostly to China.
"It's a shame we've had all these challenges because if not we would have had 60 people working here by now," said Gleissner.
"We've had people phoning asking for jobs throughout Covid and when we will be expanding. We're aiming to hire as many locals as we can and will be providing training. All people need is the right attitude.
"We will have our head office here on site, our accountant, our HR department, everything. Nothing will be outside of the local area."