Kevin O’Dwyer said an additional €1.9m was required yearly for the next 12 years to pay off loans on the Curraheen facility near Cork City.
“It’s not easy raising money these days. People are putting €10 into collections instead of €20 as they did during the boom.
“This is still very generous but people simply don’t have it to give like they used to,” he said.
The hospice caters for 400 in-patients annually and a further 700 receive in-home care.
It receives around €1m each year from the charity, the Friends of Marymount Hospice for day-to-day running costs. Funding also comes through insured beds and state aid.
Mr O’Dwyer said the people of Cork had always been loyal to Marymount and he praised and acknowledged their efforts.
Carrigaline Lions Club recently presented a large cheque which brought to €300,000 the amount of cash raised for Marymount since it started an annual charity cycle 20 years ago.
Cobh district gardaí also held a fundraising black tie ball at the Fota Spa Hotel, attended by 300 people.
“All the [hospice] rooms are single rooms now which has made a difference in terms of therapeutic impact. People now have the ability to make the rooms their homes,” Mr O’Dwyer added.
President Michael D Higgins will officially open the new headquarters on Apr 22.