ADF officers, who are managing the hotel, heard a female voice in the room of the man in the early hours of Tuesday morning.

After the officers conducted inquiries, the woman was escorted from the hotel's quarantine area and police were contacted.

When local police arrived and spoke with ADF officers, who are managing the hotel, both the 26-year-old man and 53-year-old woman, who was a guest staying at the hotel, were issued $1000 fines.

The woman was told to check-out immediately and attend a COVID testing facility before self-isolating at her Hornsby home.

The man, recently returned from overseas deployment, remains in hotel quarantine. The ADF is conducting further investigations.