Upon recent discovery by one curious Aussie, it turns out that Coles car insurance has silently been charging male drivers excess twice the size of females.

An additional $600 excess is charged for male drivers aged 21 to 24 who make a claim on their car insurance, while women only face an extra $300.

Men under the age of 21 are also expected to pay $300 more than females the same age, which totalled to $1,200 and $900, respectively, as reported in the Daily Telegraph.

RELATED: How to switch car insurance policies

And unfortunately this isn’t an uncommon occurrence, as Mozo research found that on average men pay $107 more than women when it comes to their car insurance - a figure which isn’t necessarily based on their driving skills or ‘riskiness’.

“In reality, this might just reflect the fact that men are more likely to drive certain types of cars, or that more women park in a garage,” says Mozo Director, Kirsty Lamont.

However, Insurance Australia Group (IAG), underwriter for Coles insurance said that the hefty price is because men make more claims than women.

IAG also confessed that this clause is not included in the Coles insurance PDS and is only disclosed once the product has been purchased.

RELATED: Young Queenslanders still forking out the most for car insurance despite surge in older drivers

But consumer group Choice believed that providers need to be clearer when advertising financial products.

“Insurers who charge certain drivers more because of their age should clearly disclose this information on a quote. This would allow consumers to more easily compare offers or shop around for a different car to reduce their excess,” said Choice spokeswoman, Stefanie Menezes.

Ways to save on your car insurance policy

Go second hand - Buying and owning a new car is the dream for many car fanatics, but Mozo research has shown that insurance quotes are lower on older cars.

Beef up security - Being too safe is never a bad thing, especially when it comes to your car insurance, as many providers will offer discounts for cars with additional security systems.

Bundle your policies - Also on the hunt for a better value home and contents policy? If you bundle these up under the same provider, you could receive a discount of up to 50%!

Compare, compare - Our final tip is to shop around online on car insurance policies. There are a number of discounts floating around simply for applying online.

Ready to start your shop? Compare a range of deals online with our car insurance comparison tool.