Campaigner Garry Burns wrote to the board's president in December complaining about Folau's infamous Instagram post in which he warned hell awaits homosexuals.

Mr Burns also complained about the player's comments in a video church sermon linking severe droughts and unprecedented bushfires to the legalisation of same-sex marriage in late 2017.

But ADB president Annabelle Bennett this week wrote to Mr Burns "declining" the complaint because she was satisfied it was vexatious and "a flagrant abuse of process such that no further actions should be taken".

She found Mr Burns had not pursued the complaint under the state's Anti-Discrimination Act "in order to avail himself of the processes afforded under the ADA but for a collateral purpose, as a means to pressure the respondent to settle with him".

The president wrote that the inference was that the settlement sought by Mr Burns was "directed to the payment of money".

She noted the activist had disregarded the confidential nature of the process by issuing a media release which stated, in part: "Fellas, I'm just like a vicious Alsatian dog. Once I grab hold of the leg, I don't let go until the bone is bare and bloodied. One way or another, I will get that remedy from Mr Folau."

Dr Bennett also wrote that Mr Burns had sent numerous "inappropriate" emails to Mr Folau's lawyers.

In response to Wednesday's ruling, Mr Burns has written to the Anti-Discrimination Board seeking his complaint be referred to the NSW Civil and Administrative Tribunal.

He stated that Folau's alleged breach was public "and so is my work in defence of homosexuals".

Mr Burns has previously demanded an apology and a $100,000 donation to charity.

Australian Associated Press