Guide · 12 Oct 2026 · 3 min read

Are pet doors a security risk? An honest guide to placement, size and locking

Any pet door is an opening in your house, and no pet door is burglar-proof. But a few sensible choices about size, position and locking make a big difference. Here they are.

By the Pet-Tek International team, Auckland — designers of Catwalk® and Dogwalk® since 1999.

Dog asleep on its bed in the evening beside a white Dogwalk dog door fitted low in a dark back door, well below the handle and lock

“Will a pet door let burglars in?” It is a fair question, and the honest answer is that any pet door is an opening in your house, so no pet door is burglar-proof. The good news is that the real risks are easy to understand and most of them are within your control. They come down to three things: size, position and locking.

1. Size: choose the smallest door that fits your pet

A cat door is far too small for a person. A large dog door is a different matter: a big enough opening can let a small person climb through, or let someone reach an arm inside. So size the door to the pet you actually have, not one size up “just in case”.

Measure your pet’s shoulder height and widest point (how to measure).
For many small and medium dogs, the Dogwalk® Intermediate (216 × 237 mm opening, dogs to about 380 mm) or the Small Dog Door (180 × 227 mm) is enough, and a smaller opening is a smaller risk.

2. Position: keep it low and away from the lock

The most common worry is someone reaching through the pet door to open the house door from the inside. Make that impossible:

Fit the pet door low, at your pet’s belly height, and as far from the handle and lock as the door allows.
Never leave a key in the lock, and keep spare keys, car keys and handbags away from the door.
Think about thumb-turn locks and lever handles near the pet door; if an arm could reach them, the pet door is in the wrong place.
Glass is often the better spot. A glass-fitting door in a fixed panel or the fixed side of a slider puts the opening well away from any handle. Our sliding door guide explains how.

3. Locking: use the 4-way dial

Every Catwalk® and Dogwalk® door has a factory-fitted 4-way dial: open both ways, in only, out only, or locked. Make locking it a habit:

Locked at night and whenever the house is empty with the pets inside.
In only in the late afternoon so pets can come home before you lock up.
On the glass-fitting Dogwalk® doors, a security clip holds the dial in the locked position.

A worn or broken dial is worth replacing straight away; genuine dial sets are on the spares page.

Other animals: a different kind of security

For many cat owners the real intruder is the neighbour’s cat eating your cat’s food. The Catwalk® Multi-Magnetic stays latched until a cat wearing its collar magnet comes to the flap, with no batteries. For microchip-reading flaps, see our microchip vs magnetic guide.

Alarms and insurance

Alarms: pets moving around at night can set off motion sensors. Ask your alarm company about pet-friendly sensors or zones.
Insurance: policies differ. Some insurers ask about pet doors, especially large dog doors, so check your policy wording or ask before you fit one.

The short version

Smallest door that fits the pet, fitted low and away from the lock, no keys nearby, and locked at night and when you are out. Questions about your setup? Email info@petnest.co.nz with a photo of the door.

Quick answers

Can someone get in through a pet door?

Any opening is a possible weak point, and no pet door is burglar-proof. The main risks are a person reaching through to a handle, key or lock, or a small person climbing through a large dog door. Choose the smallest door that fits your pet, fit it low and away from the lock, and lock it when you are out.

How do I make my dog door more secure?

Fit it as far from the door handle and lock as you can, never leave a key in the lock, and turn the 4-way dial to locked at night and when the house is empty. On the glass-fitting Dogwalk doors, a security clip holds the dial in the locked position.

Do pet doors affect home insurance?

It depends on your insurer and policy. Some ask about pet doors, especially large ones. Check your policy wording or ask your insurer before you fit one.

Shop this guide

The doors in this article

Ships from Auckland · courier NZ-wide · free shipping over $250 · 3-year warranty

Ready to choose?

Three taps to the right door

Tell us the pet and the door it goes into; we name the model.

Find your door →