Hi @Patrick1063 HFC flavour NBN is delivered via coaxial cable, usually via a pre existing pay tv type cable, you won't require that existing phone socket, however it may be advantageous to leave the cable there as an option so you can position a cordless base/answering machine in the kitchen for ease of use when the NBN is installed, a UTP cable from the kitchen to wherever the NBN router ends up being will give you that option, leave it in if only as a draw wire for the future and install a blank wall plate at that spot.
If I were you I would keep the cable or as you are renovating, replace it with a length of CAT6 cable.
I am also with HFC and the modem supplied provides telephony via VOIP and there are two phone ports on the HG659 modem. What you could do is to wire up one of the ports to come to the kitchen, or better still, disconnect house telephone wiring from Telstra line coming in from the street and connet the house phone wiring to a phone port on the modem. That way any existing phone socket can be used to connect to a wired phone.