PATIENTS may get better on-the-spot care in emergencies with the transfer of part of the ambulance service to the Hospital Authority. The authority will begin to take over the non-emergency ambulance service from the Fire Services Department (FSD) from October, and by 1995 will be providing 90 per cent of the service. The FSD will continue to provide the remaining 10 per cent until an organisation has been identified to take it over. The Secretary for Security, Alistair Asprey, said the plan could minimise costs by using less of the specialised vehicles, highly-trained staff and sophisticated equipment provided by the FSD. ''It is proposed to use part of these savings to expand the paramedical services of the Fire Services Department to upgrade the standard of on-the-spot care for patients in emergencies.'' But Mr Asprey said funds for the FSD would be reduced in stages to enable it to maintain its existing level of emergency services and the remaining non-emergency ambulance service. ''Sufficient resources will, at the same time, be made available to the Hospital Authority to enable it to take up the non-emergency service in stages,'' he said.