Appearing on Thursday’s This Morning show, the 49-year-old told hosts Gethin Jones and Kimberley Walsh that he wished he had done things differently.
“When you get a terminal diagnosis, [the insurance] covers you for when you’re gone,” he said.
“But a terminal diagnosis can go on for years and it will affect… your illness affects your work, so if you’re unable to work and you’re waiting for this payout, who is going to pay the rent?
“So critical illness is a policy you take alongside that and that kicks in as soon as you’re ill.”
Failing to do so has proved to be a major source of stress for the broadcaster, he said.
“I didn’t take that and that put a lot of pressure on having to work on days when I didn’t want to go to work, and that’s one mistake I say to everyone,” he said.
Irwin first became aware something was wrong during filming in August 2020.
After experiencing blurred vision while driving, he sought medical advice and was “given six months to live”.
The host initially kept his illness a secret, but went public earlier this month after learning the cancer had spread from his lungs to his brain.
He told Hello! magazine, that he “doesn’t know how long I have”, but hopes his words will inspire people to “make the most of every day”.
His comments come after claims he was dropped by the Channel 4 show after he told them about his terminal diagnosis, alleging that the broadcaster “pushed him aside for someone healthier”.
Despite expressing a wish to continue working and assurances to provide doctors’ notes and assurances from his oncologist that he was fit to work, he was told “verbatim, ‘Oh, you really don’t want to go down that route, do you?’”
“They said, ‘We don’t think we can get the insurance,’ not ‘We can’t get the insurance,’ but, ‘We don’t think…’ That broke my heart and affected my mental health,” he told The Sun.
Just two weeks later, “someone else was on TV doing my job”, Irwin said, adding: “I just feel I’d earned a bit more from them after 18 years.”