Japanese property developers have been questioned in parliament about a widening construction scandal.
Susumu Ojima denied he was complicit in the fraud
The scandal broke earlier this month when an architect, Hidetsugu Aneha, admitted falsifying data to cut costs.
The admission - in one of the world's most earthquake-prone countries - raised fears that buildings he designed may not be earthquake-proof.
Hundreds of people have already been evacuated from apartment blocks and hotels deemed to be at risk.
One of the property developers questioned on Tuesday, Huser Management Ltd president Susumu Ojima, said his company had merely followed plans drawn up by Mr Aneha.
Mr Ojima said he did not know that they were sub-standard.
"Let's remember that these plans were drawn up by one individual, a crook," he told a lower house committee hearing.
Ruling party lawmaker Rokuzaemon Yoshida said the situation was extremely serious.
"This issue has stunned the whole nation, brought fear to the lives of innocent citizens, and taken away many people's livelihoods," he said.
Japan's Land, Infrastructure and Transport Ministry has found that Mr Aneha faked data for at least 21 buildings. It is planning to bring criminal charges against him.
But Mr Aneha has reportedly designed many more than that - nearly 200 buildings in at least 20 prefectures - and investigations are continuing.
He admitted that even in the course of a moderate earthquake, his buildings "might crumble".
"I felt pressure from the industry's overall trend to seek speed and low cost," the architect told reporters.
The BBC's Tokyo correspondent says Japan's construction industry is beginning to recover from a decade of economic stagnation, but there is still fierce competition to win contracts.
Japan has been scrambling to ensure its architecture is quake-proof ever since more than 6,400 people died in a 7.3 magnitude tremor in the western city of Kobe in 1995.
But some of the bodies responsible for inspecting building work have admitted they do not always read the detailed reports submitted by architects, according to our correspondent.
The government has now promised to set up a special team to inspect the inspectors.