PATIENTS suffering from three serious diseases - cancer, heart disease and kidney failure - will benefit most from plans to step up care for the chronically ill. Heart disease patients are expected to be the target of a major rehabilitation effort by the Hospital Authority next year. And the 500 new hospice care places to be introduced in 1994 are aimed at catering for the 8,000 people who die from cancer annually. But while doctors welcomed the move to target chronically ill patients, which they said was long overdue, they criticised the $32 million set aside for rehabilitation services as being far too little. ''Nobody knows how many chronically ill patients there are,'' Dr Jonathan Sham, of Hong Kong University's department of radiation and oncology, said. ''But there are perhaps around 100,000.'' He said chronically ill patients urgently needed psycho-social services as well as more technical and medical aid, to help them deal with their long-term, disabling conditions. ''This is a good start but it is just a start,'' he said. Several groups were disappointed with the provision for kidney patients. Dr Ignatius Cheng Kum-po said providing renal dialysis for an extra 135 kidney patients would cater for only some of the 200-odd new patients seen each year. And Lawrence Lam Yin-ming, convenor of the Kidney Action Group, said it was more important to step up public education to encourage organ donations because renal dialysis could not cure kidney patients. Hospital Authority director of operations Dr Yeoh Eng-kiong said the $565 million Hospital Improvement Programme was not just aimed at improving hospitals' appearance. It would also enable the Hospital Authority to make services more convenient for patients. During renovations, however, services would be redesigned to cater for the patients' needs, he said. Dr Yeoh said plans to upgrade training of nurses would be a major boost both for the profession and for patient care.