(Bloomberg) -- The safety requirements that led Toyota Motor Corp., Honda Motor Co. and other Japanese carmakers to falsify certification tests may be overly stringent and outdated given advancements in automobile design and technology, fueling calls for their review. 

Despite revisions since the standards were enacted in 1951, regulations haven’t kept up with the times, Takaki Nakanishi, an analyst at Astris Advisory Japan KK, wrote in a report. Although Akio Toyoda, chairman of Toyota, apologized earlier this week for failing to take proper steps, he also pointed to gaps between tests carried out in the field and the procedures required during the certification process.

As government officials raided Toyota’s headquarters Tuesday, the carmaker halted shipments of three cars: Corolla Fielder, Corolla Axio and Yaris Cross. Even so, the latest round didn’t include warnings over operational safety. There doesn’t appear to be any evidence of an “organizational cover-up at this stage” by the manufacturers, according to Nakanishi.

“This could present an opportunity to reform a certification testing system that’s out of kilter with actual conditions,” Nakanishi wrote.

Toyota’s three models in question account for less than two per cent of the 11 million vehicles automaker produced last year. Shipment halts will impact two assembly lines responsible for the production of about 130,000 units a year, according to the carmaker.

The latest certifications scandal comes on top of others disclosed over the past year that pose a reputational risk for the broader group of Toyota companies. In December, an internal probe of Daihatsu Motor Co. showed most of its vehicles had not been properly tested for collision safety. Toyota Industries Corp. also suspended all engine shipments in January after an investigation revealed it had falsified power-output figures.

The latest emerging scandal is “extremely regrettable,” Ken Saito, the minister of economy, trade and industry, said during a news conference in Tokyo, adding the agency is investigating the impact on suppliers and will respond appropriately.

Toyoda, grandson of the company’s founder, cited an episode at a dealership where some maintenance steps were omitted when examining cars with improved performance and precision, resulting in them being tagged as fraudulent inspections. 

“This will provide an opportunity for the government and original equipment manufacturers to work out whats best for customers, the competitiveness of the Japanese automobile industry, and how to go about the certification system itself,” Toyoda said.

The system requires auto manufacturers to notify the transport ministry in advance of the production and sale of new vehicles, to be examined for conformity with safety standards.

“In many cases even if the certification process was not followed exactly, tests that were effectively even more rigorous were subsequently conducted in many instances,” Arifumi Yoshida, an analyst at Citigroup Global Markets Japan Inc., wrote in a report. “This incident is likely in our view to trigger a push to review the certification process.”

Honda was found to have fabricated data related to noise and gasoline engine output, affecting more than three million units under 22 models including the Accord and Odyssey. The automaker didn’t find any falsification for cars currently being sold, or for upcoming models, it said.

Separately, Mazda said it falsified test results and tampered with the units used for collision testing in five models, including the Mazda2 and Roadster RF. Irregularities were identified in over 150,000 units the automaker has produced since 2014 for the Japan market.

“If no problems were found despite deviating tests, the question becomes what were the procedures and conditions stipulated by the certification system in the first place,” said Bloomberg Intelligence analyst Tatsuo Yoshida.