Absolutely!
Most Kiwi homes have internal wiring already. This is how your jack-points (and the phones, internet routers, SkyTV boxes and medical alarms that connect to them) link back to copper feed coming into your home.
When fibre is installed, the copper coming into your home is replaced by a shiny new fibre cable. However, that copper wiring throughout your home stays, meaning the jack-points continue to work for phones. Your router's location may change though, as this will need to be connected to the fibre box (ONT) installed in your home.
Newer homes may have structured cabling in place, meaning all data / phone ports link back to a central location. If this sounds like your home, then the fibre box will be installed there and everything will continue to work as before. Post-connection, we have Now field resources that can be deployed to resolve any teething issues. We won't leave you hanging like our competitors would. Ouch.
Every home is different, so give us a call and we can help.