European companies have to scale up to compete at a global level, and the European Union needs to review its approach to their growth, Spanish Industry Minister Jordi Hereu said on Wednesday.

"We need to make a great effort to have the necessary scale, and in this the European Union has to rethink these issues," Hereu said at an event organized by Spanish energy firm Naturgy in Madrid.

"That means having the right scale to compete in the world," he added.

Hereu called on the bloc to base its approach on research such as the 147-page report presented by former Italian Prime Minister Enrico Letta in April which urged a reboot of the EU single market to allow European companies to grow.

Increasing scale is necessary for European firms to catch up with rivals in the U.S., China and elsewhere in a global race in new green and digital technologies, Letta said in the report.

His findings sparked a debate on whether to bend antitrust rules to allow companies to merge and become larger and better able to compete with U.S. and Chinese giants.

EU antitrust chief Margrethe Vestager rejected any change in merger rules, as she considered the best way to create companies strong enough on the international markets is to foster competition.

(Reporting by Pietro Lombardi; Editing by Inti Landauro and Jan Harvey)