The consumer watchdog is taking Samsung to court for marketing many of the four million Galaxy phones sold in Australia as suitable for use in pools and oceans, despite knowing they were not sufficiently water resistant.

The Australian Competition and Consumer Commission has instituted Federal Court proceedings against Samsung alleging the electronics giant misled and deceived customers with representations of various Galaxy phones across more than 300 advertisements since February 2016.

Ads across social media, online, TV, billboards, brochures and other media depicted the phones being used at pools and beaches, while Samsung also advertised them as being water resistant up to 1.5 metres for 30 minutes.

One ad showed a phone being used under water at a pool, another described "capturing your Saturday surf session at the beach", and another showed a man floating on an inflatable with a water-splashed phone on his sternum.

The ACCC says the ads are false, misleading and deceptive because the phones were not suitable for use in all types of water, which Samsung acknowledged on its website by advising against using the Galaxy S10 at the beach or a pool.

"Samsung showed the Galaxy phones used in situations they shouldn't be to attract customers," ACCC chair Rod Sims said on Thursday.

"Under the Australian Consumer Law, businesses cannot mislead consumers about their products' capabilities."

Samsung said it intends to defend the proceedings.

"Samsung stands by its marketing and advertising of the water resistancy of its smartphones," Samsung Australia said in a statement.

"We are also confident that we provide customers with free-of-charge remedies in a manner consistent with Samsung's obligations under its manufacturer warranty and the Australian Consumer Law."

The ACCC alleges that Samsung did not sufficiently test its phones to back its advertised claims, and denied warranty claims from users whose phones were damaged in water.

Samsung's Galaxy phones advertised as water resistant typically cost more than those that are not, the ACCC said.

"Samsung itself has acknowledged that water resistance is an important factor influencing Australian consumer decisions when they choose what mobile phone to purchase," Mr Sims said.