Yes, most companies will consider it as fraud and void your policy. The consequences are mentioned in the policy. Always make sure your information is 100% accurate. Insurance Companies have decline many claims when they have found any fraudulent information.
Ex. A case in the United States: A man had misrepresented information about his tobacco chewing habit and he got a non-smoker policy. He later was diagnosed with cancer and passed away in two or three years of policy issued. Insurance company had investigated the case and decline his claim due to fraud.