looking through all the results of top divisions, and Chatham cup/ knockout cup finalist no one has had a perfect season, the closets being waitak who have won every cup and league game except for 2 draws.
Caversham for example perfect season should mean winning the cup too!
While Waitakere won the league and cup in 1995 they did lose 1 game in the regional round of the superclub (1-0 to Waikato United)
The closest to a perfect season is Eastern Suburbs in 1965 when they won the Northern League unbeaten, with 2 draws and they also won the Chatham Cup
Caversham's 18 wins from 18 games is the first time a men's team has done this in NZ (in a top level division)