The European Aviation Safety Agency has recommended that companies suspend use of Kobe Steel products when possible.
The recommendation on the agency's website follows the company's admission that it has faked inspections data on products sold to hundreds of companies.
The agency said companies should thoroughly review their supply chains to identify "suspected unapproved parts" from Kobe Steel that they may have used.
"Where alternative suppliers are available, it is recommended to suspend use of Kobe Steel products until the legitimacy of the affected parts can be determined," the notice says.
It says the directive did not indicate an "unsafe condition" requiring further immediate action such as an airworthiness warning. But the agency said it had contacted Japanese authorities for more information.
Kobe Steel had no immediate comment on the announcement.
The 112-year-old company is a major supplier of many metal products used in aircraft, trains, vehicles and other equipment. Company officials say the company is still trying to determine the full extent of the problem.
The metals and equipment maker said late Tuesday that it would "sincerely cooperate" with an investigation by the U.S. Department of Justice.
Japan's Mainichi newspaper and other local media, citing former Kobe Steel workers, have reported the problems began more than 30 years ago.
The company has reported it discovered bogus inspections or faked data for steel powder, aluminum flat-rolled products and castings, copper strips and tubes and forgings, among many other products.
It has acknowledged the fudging of inspections data might have begun up to a decade ago and affected more than 500 customers.
Japanese government officials and the company itself say it is unclear if the improper reporting poses a safety hazard. In some cases, company officials say, the products might actually exceed customers' specifications, depending on the situation.
But the problems are the latest in a slew of product quality, accounting and corruption scandals that have dented Japan's image of superior manufacturing prowess.
Associated Press writer Mari Yamaguchi contributed to this report.