Many European countries have banned Chinese companies from all or part of their 5G networks on security grounds, amid intense diplomatic pressure from the United States.

But Huawei accounts for 59% of Germany's 5G RAN - the base stations and related infrastructure that connect smartphones to the network - compared to 57% in 4G networks, according to the survey by telecommunications consultancy Strand Consult.

The survey, to be released next week but seen by Reuters, provides an overview of the roles of China's Huawei and ZTE in the roll-out of next-generation mobile networks across Europe, singling out the region's largest economy for its continued reliance on its top trade partner.

"There are indications that Germany has not taken the security threat that China poses seriously," the study says, drawing comparisons to the Nord Stream 2 gas pipeline, long criticised by opponents as a security risk but which Berlin justified by saying Russia would not weaponise energy.

Huawei has repeatedly denied its equipment poses a security risk and accuses Washington of a protectionist desire to help U.S. firms that cannot compete with its technology and pricing.

Huawei did not immediately reply to request for comment for this story.

Germany, home to operators like Deutsche Telekom and O2, passed an IT security law two years ago setting high hurdles for makers of telecommunications equipment for the "critical components" of 5G networks.

Critics note requirements are toughest for the core network, where sensitive data is processed, but say that is so enmeshed with RAN infrastructure that both can pose security risks.

The German network agency referred Reuters to regulation that shows differentiated treatment for core and RAN components. The information security office did not reply to a request for comment on whether the high share of Chinese components could pose a security threat.

Jens Zimmermann, a lawmaker for the Social Democrats (SPD), the senior coalition party in the German government, accused telecoms operators of sticking to the minimum requirements of the new law rather than its spirit.

"If this attitude continues, we will need to tighten the legal framework," the SPD spokesperson for digital policy said.

GERMANY COULD TIGHTEN REQUIREMENTS

The Strand report shows that while Germany is not alone in increasing its use of Chinese-made RAN gear in its 5G network, many small European countries, especially the Nordics and eastern states like Estonia, Latvia, Lithuania and Slovakia, do not use any.

In some of those countries, author John Strand told Reuters, operators themselves had chosen non-Chinese vendors to keep wary corporate customers happy.

The report noted, however, that Huawei has a higher market share in Berlin than in Beijing, where it faces tough competition from domestic rival ZTE.

A strategy paper by Germany's Greens-run economy ministry has recommended increased scrutiny of components from authoritarian states in critical infrastructure.

"We need a general revision of commercial cooperation with companies from autocratic states," said Greens lawmaker Konstantin von Notz, chairman of the parliamentary committee that oversees the intelligence services.

A more pro-active approach was needed, he said, to ensure Germany's sovereignty "in the face of states like Russia and China".

(Reporting by Sarah Marsh; Additional Reporting by Supantha Mukherjee in Stockholm; Editing by Kirsten Donovan)

By Sarah Marsh