If you suspect that your partner is being unfaithful, there are a few different ways that a private investigator can get evidence. Much of it depends on the situation and how much information you can provide us to start with. And there are various legal boundaries that dictate exactly what we can and can’t do.

Here are some common questions we get asked.

Can you put a GPS tracking device on their vehicle?

There are some situations where it is legal to track a vehicle. We can only put a tracking device on it with the consent of one of the registered owners of the vehicle. So if you are one of the owners of the vehicle your partner drives, it may be ok.

Can you monitor their phone or computer?

In most cases, no. We certainly can’t ‘hack’ into any of their electronic devices. However, you, as their partner, may be able to monitor some of their behaviour. Especially if you share accounts or devices. And you may be able to pick up on any behavioural or habit changes which could indicate infidelity. I.e. if they’re being more secretive with their phone, have a second phone or open another social media account etc. Things like text messages, emails, or other social media activity are all things to keep an eye on if you can.

Can you follow my partner?

Yes. Surveillance is one of the most common ways to get proof that they’re being unfaithful. This includes conducting surveillance on their house, or following them on foot or in a vehicle. We can find out a lot by following someone, and we do this type of work all the time.

As their partner, you’ll probably have a fairly good idea of when you suspect they’re meeting up. If you can take note of their behaviour and patterns, we can tailor our surveillance to suit. We can also be on standby and able to respond pretty quickly.

Can you provide photo or video evidence?

Yes, however there are some limitations under the Privacy Act 2020. A simplified version is that we can take photos or video of someone in a public place where there is no expectation of privacy. So we could photograph them together in a restaurant, at a park etc. We wouldn’t be able to photograph them inside a house, or another area where there is a reasonable expectation of privacy. However, we may be able to observe and report on what we see inside their house if it’s from a public place (without taking photos).

Can you find anything out online?

Yes. Most illicit affairs are kept fairly secret and offline, however there may be some indicators on their social media profiles, or profiles of their friends. This is usually one of the first places for us to start looking into them. There may not be anything definitive, but it can help guide our investigation.

What else can you do?

We can interview people who know your partner, such as friends, family members, or co-workers, to gather information about their behaviour and activities. This can be risky as it could get back to your partner, and then they hide their activities even more. But there are also discreet ways to do this.

We can also do a background check to see if they have any previous history of cheating or other suspicious behaviour. This information can be harder to find but worth looking for.

How much will it cost to investigate them?

This really depends on how much information you can give us up front, and how secretive your partner is.

Surveillance is a big unknown. Sometimes we can watch them for hours or even days and see nothing, in other cases they meet up with their lover almost straight away.

Yes, we can watch someone round the clock for the entire week and we’d probably catch them. But that would cost you, the client, thousands of dollars. Better to try and narrow down some time slots to when they’re likely to meet up with their lover.

In many cases, you’d be looking at a minimum of two night’s surveillance which may be around $700. We can’t guarantee we’ll see something, but the more background information we have the better.

What can I do?

Before engaging us, there are a few things you can do. These can help you process what’s going on and maybe confirm some of your suspicions. And if you do end up hiring us, they can help us get a potential result quickly.

The first thing is to not raise their suspicions. If they feel like they’re being watched or scrutinized this will only make them more secretive. Don’t change anything yet. Observe but don’t confront or make them aware that you’re watching them.

Take a look through our guide on how to tell if your partner is cheating on you. How many of the signs have you spotted?

Have a look at our various blog posts on cheating partners:


Take note of as much evidence as you can. The more information you can give us, the quicker we can get a result. Most of these cases are solved with surveillance. The key thing is figuring out the most likely times that they meet up with their lover. If you can narrow this down, it will mean less surveillance hours wasted.

Can we help you? If you need an Auckland private investigator contact us on 09 391 1100 or help@isolve.nz for a chat.

iSolve – For when you need to know.