Largest NZ domestic crowd

Largest NZ domestic crowd

I know that there has been a claim that last weeks Nix game had the largest crowd for a domestic game in NZ. Sorry but it wasnt, close but not quite.
The biggest crowd at a domestic game in NZ was 17,690 when Mt Wellington lost 1-0 to Wellington City in a Chatham Cup semi final in 1971.

can you back this claim up?

Sure, its in a book by Terry Maddaford called 100 years of Football 1887 to 1987

google search no record

same author writes this:

Well I will have to remind him of what he wrote in 1987