"So I am not against it, but the only way I would support it is if it met those four criteria."
He said at this stage while such a scheme had great job potential for the region, if it were to go ahead it would be because the farmers saw value in it.
"I think gone are the days where we can put this much money at risk with the sort of 'build it and they will come' mentality," he said.
"The farmers themselves are the only ones who can determine if this goes ahead because if they see [the value] they will sign up if they don't, they won't."
And here, the MP said lies the major challenge faced by the scheme - convincing the land owners that there is value in it they should be investing in the RWSS.
"It is a substantial amount of money, my understanding is it is about $280 million just to get the water from the dam on to the farm," he said.
"So it is convincing the land owners that there actually is value over and above the cost of the scheme itself.
"So you and I won't determine if this goes ahead [or not] it will be determined by those land owners."
Tukituki MP Craig Foss agreed with Mr Nash about the opportunities such a scheme would bring to the region.
"This is a $250 million investment in Hawke's Bay " the largest our region has ever seen," he said.
"This project is about boosting our exports and job opportunities throughout the region - from the farms of Central Hawke's Bay, to the processors in Hastings, to the port, shops and restaurants in Napier," he said.
"It's also about families, about having an economy that can support good wages and salaries and attract our kids back to the region."
He said the project has surmounted many, many challenges.
"But some still remain, including the legal process, take-up by users and confirming final investors," he said.
"Environmental, geological and agricultural experts have examined and tested the proposal and it continues to progress, albeit frustratingly slowly."
Central Hawke's Bay Mayor Peter Butler lamented his district was "sitting here with fingers crossed and bated breath waiting for the go button to be pressed".
He said one of the main benefits such a scheme would bring was jobs.
"I believe Central Hawke's Bay will explode - in a positive way.
"Go down to Canterbury and just see what water can do for flat farms - just amazing."
He said while the challenge of the judicial review lodged by Forest and Bird over the Smedley land swap was still on the horizon, the district was just waiting for the scheme to begin.
"We have got 200 extra people in the CHB - what is going to happen when the go button is pressed?"
Regional councillor Rex Graham said he though the water was still too expensive for people to sign up.
"I don't think the security there is strong enough I think the risk to ratepayers is too high because threshold risk is too high," he said.
"Nevertheless, that is my personal view. Council, by majority, agreed to invest the money and that is our democratic process and I will live with that, as long as the farmers buy the water, as long as we meet the conditions precedent.
"So no matter what I think or what anyone else thinks, if the farmers buy the water it will go ahead."
Mr Graham did mention the upcoming date of November 11 " the date set for farmers to sign up to the scheme so the company could meet the condition precedent of the water contract threshold.
"We were told the 11th was the deadline but there is no way they can meet it by the deadline," he said.
"If the 11th is the deadline then that will be a very interesting day."
Fellow regional councillor Alan Dick said he was pretty confident that they will see the "go button" being pushed.
"The region needs game-changing investments and that is one and the benefits will flow from central Hawke's Bay right thorough to Napier and beyond," he said.
"I just believe as long as it potentially ticks all the boxes and that it is economically viable and that financially self- sustainable and it meets its environmental objectives - then it is a must do for the region
"And I am pretty confident that it will see the go button being pushed not necessarily next week, but early next year at this stage."
