Tenants authorising NBN work on common property

Hi,

Our building has existing Foxtel cabling to every unit and the strata committee has written to the NBN to ensure that this cabling is used to connect the units to the NBN.

Meanwhile we have people claiming to be from the NBN or an ISP turning up and drilling through walls in common areas and attaching cables to walls based on a request from tenants for an NBN plan.

Is the NBN or an ISP entitled to make changes to a building without authorisation of the unit owner or the owners corporation?

Thanks