Approximately 2,800 people will be diagnosed with bowel cancer this year, with 1,000 dying according to the Irish Cancer Society.
It comes when patients wait more than three months for a colonoscopy.
The Irish Cancer Society is calling for "urgent action" to be taken, as nearly one in two patients is affected by longer waiting periods.
The head of services at the Irish Cancer Society, Donal Buggy, said capital investment in capital is needed to ensure there are enough endoscopy suites for all colonoscopies to be made.
"We also need to have doctors so that gastroenterologists work on our services to ensure that patients who are waiting for these savior tests receive them in a timely manner."