(Adds background, details, Boyner group decision)
ISTANBUL, Oct 8 (Reuters) - Turkey has asked more than 100 companies to explain what it says are excessive price increases of goods, it said on Monday, in a probe into suspected price gouging after a currency crisis pushed inflation to a 15-year high.
The move comes after President Tayyip Erdogan last week called on Turks to report unusual price hikes in shops, saying it was the government's responsibility to raid the inventories of stores if necessary.
The lira has fallen 40 percent this year. Erdogan, who has cast the sell-off as an economic attack on the country, has said fines would be imposed against "opportunists" who took advantage of the selling to aggressively raise prices.
The Trade Ministry said on Monday it had asked 114 companies for explanations of the price increases, after inspecting more than 69,000 products at nearly 4,000 companies.
The investigation was not aimed at intervening in the free market, but to prevent unfair price hikes, it said. It did not give information about the companies or products suspected of excessive price increases.
As the currency crisis deepened in August, the government made it illegal for companies to arbitrarily impose price increases if they were not impacted by a rise in input costs or the exchange rate.
Separately, Boyner Group, one of Turkey's top clothing retailers, said it would introduce a 10 percent discount on the products of more than 30 affiliated brands to help counter inflation. The size of the discount will increase in the future, it said.
Finance Minister Berat Albayrak, Erdogan's son-in-law, is due to announce a programme for a "full-fledged fight against inflation" on Tuesday.
Inflation surged to nearly 25 percent in September, data showed last week, hitting its highest in 15 years and underscoring the deep impact of the currency crisis on consumers. (Reporting by Nevzat Devranoglu and Ceyda Caglayan Writing by Ali Kucukgocmen Editing by David Dolan and Toby Chopra)