During a taped conversation with Ms Fraser's ex-husband last August, Mr Ruka promised the money would be returned by last Christmas but this did not happen.
"I absolutely guarantee it," Mr Ruka said at the time. "They deserve it back.
"The fact they have agreed to take it back without interest is even better."
On this same tape - which the Herald has listened to - Mr Ruka claimed to be in charge of a trust which had the Maori King, Tuheitia, as a beneficiary.
Mr Ruka also said that $2 billion worth of gold was being brought into the trust from Europe "for the safe-keeping of the King".
According to King Tuheitia's chief adviser, Tukoroirangi Morgan, there is no connection between Mr Ruka and the office of the King.
The Herald has made numerous attempts to contact Mr Ruka but he has not returned calls.
It is not known how exactly many people have put money into his company, although the Herald has been told there are others who have put hundreds of thousands of dollars into the water-bottling venture.
Documents which Mr Ruka gave to the Frasers say the project is estimated to cost US$174 million ($207 million).
Mr Ruka first claimed he had Chinese backers in Christchurch interested in the project and then Canadian financiers, Ms Fraser said.
Investors were told last year that members of a London company, the Vitala Group, were due to visit the Kaiapoi site in September but she did not believe this had taken place.
According to forecasts given to investors, Water 3000 had the potential to make $43 million in profits during its first year of operation, $76 million in its second year and $94 million in its third year.
But the plant to process and bottle the water has not yet been built.
About the time the Frasers invested in Water 3000, the family also put $340,000 into a bullion trading firm, Grace Holdings NZ.
However, last February they were told they would not be getting their money back and the Serious Fraud Office launched a probe into thefirm.
After an 11-month investigation, the SFO charged Grace Holdings' Kairuaiti Tangata Oropai Robert Kairua, with 29 counts of theft by a person in special relationship and false statement by a promoter.