Short answer: sometimes, and less often than you are told. General information only, check your own tenancy agreement and tenancy.govt.nz.
When it is genuinely required
Your agreement has a pet clause. This is the common one, and it is usually enforceable. Many New Zealand tenancy agreements permit pets on the condition that carpets are professionally cleaned at the end of the tenancy. If you signed that and kept a pet, you agreed to it.
The carpets are actually stained or soiled beyond what vacuuming will fix. This is not really a legal question. If there are stains you caused, they need dealing with, and a machine is the way to do it.
When it is not
A blanket clause requiring professional cleaning regardless of condition is on much weaker ground. The statutory standard is that the property is left reasonably clean and tidy, if thorough vacuuming achieves that on carpets that were sound to begin with, you have met your obligation.
Fair wear and tear is never yours to fix. Carpet that has flattened in a hallway, or faded near a window, has deteriorated through ordinary use. Cleaning will not reverse it, and you cannot be charged for it not being reversed.
Carpets that were already worn when you moved in. This is what an entry condition report is for. If the carpet was tired on day one, it is not your job to hand it back better.
How to handle the conversation
Ask the property manager, in writing, before you book anything:
Is professional carpet cleaning specifically required under our tenancy agreement, or is thorough vacuuming acceptable if the carpets are in the same condition as at the start?
A written answer is useful either way. If they say it is required, ask them to point to the clause. If they cannot, you have a reasonable basis to decline, and a record of having asked, which matters if it becomes a dispute.
What it costs if you do need it
In the Waikato, $40–$70 per room for hot water extraction, with most operators applying a two- or three-room minimum. A standard three-bedroom house with lounge and hallway is usually $160–$280. Stain treatment and deodorising are typically extra.
Get the receipt and keep it. If a landlord later claims the carpets were not cleaned, an invoice naming the rooms treated ends that discussion immediately.
Our position
When we quote an end of tenancy clean, we tell you whether we think you need carpet machine-cleaning. If your agreement does not require it and the carpets are sound, we say so. Selling you a service you do not need is a bad way to earn a review.