You can take a bus from Auckland to Maraetai via Stop B Botany Town Centre in around 2 h 31 min.
How to get from Auckland to Maraetai
From 100 Park Rd line 70 bus to Stop B Botany Town Centre then line 739 bus to Opp 265 Maraetai Dr. 2 h 31 min $7. From Newmarket Train Station train to Opp 100 Hospital Rd, line 314 bus to Ormiston Town Centre Eastbound, then line 739 bus to Opp 265 Maraetai Dr. 2 h 31 min $14. From Auckland taxi to Maraetai. 32 min $152. From Auckland drive to Maraetai. 32 min $8.