Former All Black Sonny Bill Williams has won a battle for a mosque to be built in Sydney.

Williams and NRL star Anthony Mundine have donated almost $200,000 towards the mosque.

He told 9News it's been four or five years in the making and it's "long overdue".

"There's a big community of us out there you know and especially in the sporting world, we walk that same walk and we have those same struggles."

Williams said he's hoping a lot of "goodness" will come from the mosque being built.

"It's going to be something special, that contentment and happiness I feel, no one can tell me what that feels like, only I can and I feel it."

The site is currently a rundown nursing home but is soon to be a $5 million mosque and community centre.