A German clothing company says it is "surprised, shocked and appalled" after samples of its textiles were reportedly found in the remains of a Bangladesh garment factory that collapsed on the outskirts of Dhaka last week.

German news portal Spiegel Online reported Thursday that rescuers found t-shirts and tops for KiK's house brand 'okay' amid the rubble.

Authorities say more than 400 people died in the disaster.

Discount brand KiK says it hasn't had any direct business relations with suppliers based in the Rana Plaza building since 2008.

Spokeswoman Beatrice Volkenandt says the company is now investigating how its labels and textiles came to be at the site.

KiK has in the past been criticized after its clothing was found following factory fires in Bangladesh and Pakistan.