Some colleges have second and third year medical/dental/pharmacy students who do tutorials, but as I've said above, for most subjects tutorials are of debatable value anyway. If you do happen to need tutorials on a specific subject, there are almost 600 preclinical med students in Dunedin, and a ridiculous number of them put fliers up offering solo tutes for reasonable prices. One of my current registrars (NZ is a very small place, especially wrt med) was my physics/chemistry tutor in semester one of HSFY, and from memory I paid her like a total of $150 over a semester to teach me the few bits I couldn't have understood anyway. I failed high school chemistry and physics pretty badly, so was playing catch-up. Most people have fewer issues understanding those subjects than I did. The HSFY content is pretty straightforward, by and large. If you've done ok at school, you likely won't need someone to walk you through it anyway. So the hall you go to won't affect your odds of getting into your chosen course all that much. As I've said above, your own internal motivation matters far more.