Excessive noise is typically loud stereos, noisy parties and the like. Deciding whether noise is excessive is a matter of judgement for the noise control officer. Noise control officers do not use decibel reading equipment for noise complaints.
Noise in Rural Residential locations should be referred to the Planning department unless it is loud music or party type noise and then you need to call noise control as outlined above.
Construction noise is permitted between 7am and 6pm in accordance with "NZS 68030:1984 The Measurement and Assessment of Noise from Construction, Maintenance, and Demolition Work"
A breach to these standards requires a land use consent as a discretionary (restricted) activity in terms of Rule 12.7.4(ii) of the Central Otago District Plan. See Construction Noise - District Plan - CODC
You can build outside of these hours if there is not noise involved that could be heard by neighbours/others outside of your property.