It is compulsory for every child from 6-16 years to be enrolled at a registered school. However, parents or guardians have the right to apply for a Certificate of Exemption from Enrolment at a Registered School. Parents who gain a Certificate of Exemption are also exempt from having to follow the NZ Curriculum Framework Requirements. [...]

Yes, you can, both legally and practically, however it can be more difficult to gain an exemption to homeschool a special needs child. Some of the greatest achievements in homeschooling have been by parents of special needs children.