More than half of UK construction professionals feel corruption is rife in their own industry, a Chartered Institute of Building survey showed.
About 51% of 1,400 construction professionals questioned by the institute said corrupt practices were common.
About three-quarters of the construction professionals surveyed said the employment of illegal workers was widespread.
Six out of 10 felt fraud was prevalent, and 41% said they had been personally offered a bribe.
Michael Brown, deputy chief executive of the institute, said: “People define corruption in different ways.
“What is corrupt to one person might be common practice or just how it has always been done to another.
“While the majority of respondents recognised corrupt practices for what they were, there was a concerning level of people who thought, for example, that producing a fraudulent invoice was not corrupt, or that using bribery to obtain a contract was also not a particularly corrupt practice.
“We clearly have some way to go as an industry to make ethical construction the only construction.”