Online retailer Kogan misled customers with a 10 per cent discount just a day after raising prices of its products, the Federal Court says.

Kogan launched its “TAXTIME” promo code in June 2018, immediately after raising prices on more than 600 products.

In many cases the price increase was at least as much as the discount offered.

The Australian Competition and Consumer Commission took Kogan to the Federal Court, which on Friday ruled the retailer engaged in misleading or deceptive conduct.

ACCC boss Rod Sims said many customers ended up forking out as much as, if not more than, they would otherwise for the 621 products immediately before or after the promotion.

Kogan discounted those items, in many cases by at least 10 per cent, again two days after the sale ended.

Over four days in 2018, the company emailed more than 10 million customers with messages including “48 hours left!” and “ends midnight tonight!”.

It also advertised the discount on its website and sent texts to more than 930,000 customers.

Kogan defended its actions, saying they were not misleading because customers using the code received a 10 per cent discount on the price stated online at the time of the promotion.

Justice Davies dismissed Kogan’s defence against the allegations levelled by the ACCC.

It will decide on penalties for Kogan at a later date.

The company has been contacted for comment.

-with AAP