Possibly yes, it depends upon to what standard an entry door is fire-rated under the Pt 9 requirements proposed by the Developer and approved by the Local Council prior to the commencement of the Building’s construction.
Modifications to entry doors such as the deadlocks you mention (some are OK), together with security chains, spy holes or the removal of door closers can indeed compromise an entry door’s fire rating, and that’s why I suggested that Cobra first checks the wording of the relevant By-Law that’s in place at his/her Plan.
The Standard By-Law 5 (in NSW) that I referred to in my last post states that an Owner may NOT fit any additional device to an entry door if “the device is likely to affect the operation of fire safety devices in the lot or to reduce the level of safety in the lots or common property“, and yes you’re right again – some Plan-specific By-Laws include a requirement that any modifications to a fire-rated door that compromise or breach the Building’s Pt 9 Standards (e.g. a “fail”) will need to be “un-modified” and returned to a compliant state at the expense of the “modifier”.
I reiterate to Cobra, read your Plan’s relevant By-Law first!