The Road Safety Authority has confirmed it is to replace around 200,000 high-visibility vests that were found to be defective.
Speaking on RTÉ’s Morning Ireland, RSA Chief Executive Noel Brett said a reflective strip on the vests had been shown to be "marginally below" the required safety level.
The RSA purchases around 1m high-visibility vests annually to distribute to road users.
Mr Brett said that the vest in question can be identified by a tag featuring the name of the manufacturer, Optipro, and the letters RSA on the rear of the vest.
Anyone with one of the vests can have it replaced free of charge by the RSA, he said.
The vests were sourced from one supplier after a tendering process, he said.
Mr Brett also appealed for road users to take care after a spate of road deaths involving motorcyclists.
He said that 14 motorcyclists had been killed this year so far, compared to 19 in all of last year.