The head of the German competition watchdog has criticised EU draft tech regulations, saying they are too “narrow” and risk failing to catch future anti-competitive behaviours from companies such as Google and Facebook.

Andreas Mundt said Brussels must improve its Digital Markets Act proposals for reining in the power of Big Tech, which currently rely heavily on previous cases of abuse of dominance to determine which behaviours are permitted in the future.

He said the EU should instead model its new rules on the German framework, which uses a looser definition of antitrust that leaves more space to encompass new anti-competitive practices.

Speaking to the Financial Times, he said: “I think the DMA is somewhat narrow because it mirrors behaviour from the past and there might be new conduct that might be difficult to catch.”

The new EU proposals target so-called gatekeeper platforms, which own the marketplaces on which their products and services are sold and so have the power to set the rules by which they operate, often to the detriment of rivals.

Under the proposals, regulators want to ban large online platforms from preventing consumers from using alternative services and from abusing their power to give their products preferential treatment.

The European Commission has begun to rein in companies with large ecosystems, for instance opening three cases against Google since 2010 and fining the company billions of dollars for alleged antitrust violations. Google is contesting the fines and has denied accusations of breaking the law.

Mundt said: “The German law is broader and so easier to catch new strategies because the conduct from the past is given just as an example of the type of things that should be prohibited but it leaves space to identify new [anti-competitive] conduct.”

His comments came as EU countries such as Germany continue to forge ahead with their own national competition rules even as Brussels pushes for a single piece of legislation for the bloc. Using a new digital markets law enacted this January, the German competition watchdog has launched aggressive proceedings against big tech companies such as Amazon and Apple.

Mundt brushed off the suggestion that the bloc could be at risk of fragmentation if countries pursue their own tech rules. “That’s what those who don’t want national competition agencies to come in say,” he said.

“We have had powerful debates with the EU and have come to a consensus on how to apply competition law. I don’t see how we won’t do the same in any way within the framework of the DMA,” he added.

Mundt also warned that companies “underestimate” the regulatory threat as share market valuations for tech companies continue to reach new highs. “Investors don’t look at competition agencies [all] day,” he said. “But regulation is coming from all different directions, including the US, where they are also taking it seriously.”