Guiney, a Fonterra farmer-shareholder director who left the board last year after failing to make the cut to seek re-election through Fonterra's director screening process, was served with a gagging injunction by Fonterra in March.
The resulting court orders restrained Guiney "breaching her duties of confidentiality" to Fonterra and prevented media from using information received from her.
Guiney is defending the injunction in the High Court at Wellington.
She is also suing the Fonterra board for defamation over a letter it sent to Fonterra shareholders explaining the injunction action, in which the board alleged Guiney had leaked and misrepresented details of board discussions.
Guiney, who is not seeking damages in her defamation claim, told the Herald she was heartened by the shareholder support.
"This whole argument about the need for transparency, and what got me in so-called hot water, is about a better Fonterra and we won't get a better Fonterra without some sort of change, so it's heartening to know that shareholders are prepared to support me."
Fonterra, a farmer-owned cooperative, said as legal proceedings were underway, it would not comment.
Preston on the Givealittle page says "when a shareholder (or ex-director) like Leonie is being gagged, alarm bells started ringing loudly".
"A New Zealand dairy cooperative acting with this arrogance has never been seen in our history, in fact our past culture has been one of strong questioning not suppression.
"If Fonterra is to survive, this culture of bullying must stop."
Guiney was an articulate, smart woman with a "very forthright style" which should be celebrated, not suppressed, Preston said.
"Fonterra has been found wanting on many major commercial decisions it has made us in recent years costing us mega millions."
Money needed to be raised "to fund our right to speak, to challenge, to own our cooperative."
Funds raised over and above Guiney's legal defence costs would be donated to Farmstrong, a rural charity founded to support farmer wellbeing.
If legal costs were awarded to Guiney, any funds not used would be donated to Farmstrong.