UK-based NHS Blood and Transplant has reported that 40% fewer new volunteers have offered to donate blood in 2014 compared to the last decade across England and North Wales.
The NHS said 120,000 less people attended a donor session to give blood in 2014/15 compared to 2004/5.
Reported before the start of National Blood Week (8-14 June 2015), the NHS suggested that regular donations are essential to save and improve the lives of patients with cancer, blood disorders and those suffering medical trauma or undergoing surgery.
NHS Blood and Transplant donor services and marketing assistant director Jon Latham said: "We simply can’t ignore the fact that there has been a stark reduction in the number of new donors coming forward, a trend seen across the world.
"While we can meet the needs of patients now, it’s important we strengthen the donor base for the future."
The NHS collaborates with partners, including retailers and brands, media and celebrities such as Waterstones, NOW TV, Green & Black’s and Odeon Cinema to encourage blood donation.
The organisation said it requires new donors to fill gaps left by existing donors, allowing it to have the right mix of blood groups to match patients’ needs.
According to the NHS, 204,000 new volunteers should donate blood in 2015 to maintain the nation’s blood stocks at a safe level in the future.
NHS Blood and Transplant is a joint England and Wales special health authority, which is involved in the supply of blood and associated services.