SEOUL, Aug 17 (Reuters) - South Korea's antitrust regulator said it would impose a total of 33.6 billion won ($25.06 million) in fines on three domestic mobile carriers for exaggerating their 5G network speeds.

The Korea Fair Trade Commission (KFTC) said that the three South Korean teleco firms, including SK Telecom Co Ltd , KT Corp and LG Uplus Corp, had exaggerated their 5G network speeds and unfairly advertised that they were the fastest relative to their competitors.

"The three teleco companies advertised that consumers could use target 5G network speeds, which cannot be achieved in real-life environment ... companies advertised that their 5G network speed was faster than competitors without evidence," the KFTC said in a statement.

The KFTC added that it hopes this measure will serve as an opportunity for the three companies to step away from overheated competition using unfair advertisements.

SK Telecom and KT Corp declined to comment. A spokesperson at LG Uplus said the company is reviewing the sanctions.

A KFTC official said that the size of the penalty for each company would be different, and that the amounts would be made public on Thursday.

There were 30.76 million 5G network users in South Korea in June, accounting for about 38% of the total 80.23 million mobile subscriptions in the country, according to the data from the Ministry of Science and ICT.

($1 = 1,340.9700 won) (Reporting by Heekyong Yang. Editing by Gerry Doyle)