The Kidney Dialysis Foundation (KDF) expects to fall slightly short of its yearly fund-raising target, as donations have dropped owing to the uncertain global economic climate.
It costs $8 million annually to run Singapore's second-biggest non-profit dialysis provider.
Chairman Gordon Ku said that to cover the shortfall, the organisation "will be reaching out to our donors through various appeals".
This comes on the back of reports that the National Kidney Foundation, Singapore's largest provider of kidney dialysis, faces a space shortage for new patients.
The number of Singaporeans with kidney failure is increasing, and the country has the world's highest rate of kidney failure caused by diabetes.
The KDF Millennium Ride, one of the non-governmental organisation's fund-raising events, ended yesterday. In its fourth year, it sees cyclists complete a gruelling 1,000km route from Perak to Singapore in four days.
It is organised by local cycling group Epic Cyclist and raised $320,211. The group of 67 cyclists comprised people from all walks of life, from civil servants to interior designers and engineers.
Mr Gary Lee, 44, was one of the lead cyclists. After his father died of diabetes, he decided to marry his passion for cycling with charity, by taking part in the event.
Home Affairs and Law Minister K. Shanmugam, the guest of honour, said that trying to deal with issues such as kidney failure when people have developed diabetes is more difficult than making lifestyle changes.
"The only way forward is for the Government to partner NGOs like KDF... who are able to generate the passion amongst people who go on the ground and do solid, stirring work," he said.
Mr Lee, the vice-president and deputy general manager of a food manufacturing firm, said he would participate in at least two more KDF Millennium Rides.
He said: "I need to do this again for the next couple of years, to impart the skill of such extreme cycling to beginners and push fund-raising to the maximum."
Jose Hong and Seow Bei Yi
Correction note: This story has been edited to clarify that it costs $8 million annually to run Kidney Dialysis Foundation, Singapore's second-biggest non-profit dialysis provider.