One in three have been embellishing insurance applications in the hope of cheaper premiums, Zurich has said.
And according to the insurer, its recent survey also showed a third was spotting specific questions for opportunities to hold information back.
Phil Brown, head of protection and underwriting for Zurich UK Life, said it was understandable given the current economy, but added: "Failing to disclose all information at the application stage could have disastrous consequences in the long term when a future claim is rendered invalid."
The survey also showed women were more likely to provide incomplete information, with questions about weight, alcohol consumption, family history and medical health most likely to illicit partial responses.
And 4 in 10 said price was more important than having the peace of mind of cover.
Only 19% believed insurers cared about customers; more than three quarters said they tried to avoid paying insurance claims.
Last year Zurich paid out 92% of claims.
