The Fair Trade Commission is looking into five-star hotel wedding halls' tie-in sales practices, in which they make the bride and groom pay for flowers and other expenses costing millions of won.

The probe began late last year amid complaints that hotels charge exorbitant wedding fees and coerce customers into buying expensive meals, stage decor and flowers.

The antitrust watchdog secured data from the 21 five-star hotels in Seoul last week for the first investigation into unfair trade practices by hotel wedding halls since they started business in 1999.

The FTC inquiry is focused on whether the hotels forced customers to purchase certain items.

"It wouldn't be a big problem if they simply offered a full-package and optional products, but if they force the full-package on customers, it can be considered an unfair trade practice," said an FTC official

Depending on the results, the FTC may file a complaint with the prosecution against the hotels for violation of fair trade law.

It costs at least 66 million won (S$76,000) to host a wedding inviting 500 guests at a five-star hotel in Seoul.

Most hotels charge a minimum fee for flower decoration of between 3.8 million won and 20 million won.

All the flowers must be supplied by a florist designated by the hotel. The families of the bride and groom cannot supply their own flowers.

Eighteen of the 21 hotels sell wine as a mandatory part of the wedding package and 11 make the customers use the "pyebaek" room for a traditional ceremony after the wedding.

Four do not offer their least expensive menu options on Saturdays, when most weddings are held.

Stage dcor fees of up to 3.85 million won are compulsory at 13 hotels.