"Hands Across the Water was made aware several weeks ago that the Farnells were taking action in relation to accessing the Baby Gammy Special Appeal Fund," the foundation said in a statement.
"We have no information as to the justification the Farnells, or their legal team, are making to support the application for access to the funds.
"We take this matter very seriously and we are doing all that we can to defend this action to ensure the money donated remains for the care of Baby Gammy, which we believe was the intent of those who so generously donated the funds," the statement continued.
CEO of Hands Across The Water Peter Baines said he finds Mr Farnell's actions deeply concerning.
"I'm deeply concerning and perplexed that he believes that he has a claim over it," Mr Baines told Daily Mail Australia.
"We haven't received any notification of the amount, the reasoning or justification."
Mr Baines said more than $235,000 had been raised and he cannot be certain how much Farnell is seeking.
So far, the money has been used to buy Gammy's Thai family a home and to pay medical costs, and a monthly allowance is paid to Ms Chanbua.
The charity will do all that is possible to ensure the funds benefit Gammy, Mr Baines said.
When Gammy's Thai surrogate mother Ms Chanbua heard Mr Farnell tried to access the money she asked if he had "gone insane to think like this".
She told the ABC the Down syndrome boy's biological father should have no right to access the funds being used to raise Gammy, as he was the one who "abandoned" him.
"I want to ask him, 'Who do you think you are? What made you think you have the right to take it?'," Ms Chanbua said.
Mr Baines vowed he and Hands Across The Water would do everything in their power to stop Mr Farnell getting his hands on the donations.
- Daily Mail
