There are lots of agancies on the North Shore or central Auckland that can help. Do you also need a website? We run a marketing agency but do not do branding etc. Some of our clients have worked with the following with good results:
Its worth having a look at their work to see if their design resonates with you. Some offer marketing too, but I believe that they are two different disciplines (I am biased though :-))
For SEO, Google Ads etc we can help 🙂 :
For social media:
http://www.socialites.co.nz (also influencer marketing)
Speak to a few and see who you connect with. Any questions or further recomendations you can drop me an email: firstname.lastname@example.org
Other than Pure SEO I am in now way affiliated with any of teh companies I mentioned.