The chances of it happening are incredibly small, but your car key could get you access to someone else's vehicle.

Josh Bingham thought his Toyota Hilux ute had been stolen when he walked outside the Noosaville craft brewery where he works and it was nowhere to be seen.

It turns it was a few doors down the road at a mechanic's workshop, which had been recruited to service another person's Hilux.

An apprentice had been given a different key, along with instructions to go and pick it up from the side of the road round the corner, and unwittingly picked up the wrong car.

Here's how that could happen.

Josh Bingham's ute was given a surprise service by an unwitting mechanic when the keys to another car fit his. ( ABC Sunshine Coast: Alex Easton )

Car keys are not unique to one vehicle

And, if you have a car made before 1995 you could be at risk of someone having a twin key to your car.

It's hard to believe and highly unlikely it will ever happen to you but there is a possibility of someone gaining access to your car.

Andy William from Amalgamated Locksmiths said, "it has a 1,000-1 chance of happening, but it can occur in later model cars, such as cars from the early 90s that do not have transponder chip technology."

Newer car keys have a chip preventing a different key from starting an engine even if it has unlocked doors. ( ABC News )

So not only do you have to be careful of thieves, but from people mistaking your car as their own.

"I've even had it happen to myself in the 70s," Mr Williams said.

One Sydney locksmith said what happened to Mr Bingham is one of two things: "an extreme coincidence or the result of a locksmith ridging the lock on his door".

He also said that Mr Bingham's particular Toyota Hilux ute "had 5,000 possible combination series" meaning there was a one in 5,000 chance of someone having the same car key.

Even this is a low amount, as some newer cars can have up to 40,000 different combination codes.

The chances of it happening depends on the car manufacturers

There are federal vehicle standards that manufacturers must comply with when it comes to making lock systems for vehicles.

According to legislation, "the key locking system shall provide at least 1,000 different key combinations or a number equal to the total number of vehicles manufactured annually if less than 1,000."

"In vehicles of one type the frequency of occurrence of each combination shall be roughly one per 1,000."

So depending on the limit of the lock combinations on your car the higher or lower chance you have of sharing the same key with someone else.

Twin key sets could be out there for cars made before 1995. ( ABC Illawarra: Justin Huntsdale )

Can someone also drive a car with a different set of keys?

Like what happened in Mr Bingham's case yes, but it is extremely rare.

However, as new cars are made so is new anti-theft technology such as transponder chips.

These small chips placed inside the keys mean that the ignition can not start with a different key, even if it has managed to open the doors.

Barrenjoey Locksmiths and Alarms said, "transponder key technology was introduced to vehicles from approximately 1995."

And, "Australian standards require that all passenger vehicles from 2000 onwards be fitted with transponder technology."

"Some commercial vehicles and motorbikes are also fitted with this system."