Infrastructure Minister Michelle Haywood says sending patients for treatment is costing her department more than £650,000 a year.
This week in the House of Keys she faced questions about non-emergency transport from Onchan MHK Julie Edge.
Miss Edge wanted more details about the service after the DOI took it over.
Dr Haywood said it was difficult to give concrete figures for its cost:
No successful driving theory test appeals in past 10 years
Steam Packet announces tomorrow morning's sailings will go on time
Firefighter to raise money by wearing full gear in fitness competition
How much has the Department of Infrastructure claimed for property damage?
Visa fraudster convicted in Isle of Man immigration scam
Crowds gather for Maccies re-opening after £1.6m upgrade
MHK questions wages of 1,500 extra workers
Manxman sailings cancelled today