Legal changes aimed at increasing organ donations are likely to fail without an overhaul of NHS transplant services, a report by MPs and peers has warned.
Specialist staff to deal with relatives are needed, the report says
The Human Tissue Act means doctors in England, Wales and Northern Ireland can take organs from dead donor card carriers even if families object.
But the All Party Parliamentary Kidney Group (APPKG) said this was unlikely without staff to deal with relatives.
The Human Tissue Authority (HTA) hopes public faith in the system would rise.
The More Transplants, Saving More Lives report said surgeons were unlikely to want confrontation with families unless there were more back-up staff specially trained to deal sensitively with the situation.
It added that even if there were more organs available there were too few transplant surgeons and insufficient laboratory and support facilities.
The APPKG wants to see the number of transplant co-ordinators, who deal with distressed relatives, increased from 12 to 40 who would then pass on training to other nurses.
The National Kidney Federation (NKF) has backed the parliamentarians' report.
Chief executive Tim Statham said: "Despite the provisions of the Human Tissue Act we do not expect surgeons to now ignore the strongly-held wishes of relatives.
"It is more likely that the way in which grieving relatives are approached about transplantation will change.
"It will be important to monitor the impact of these changes on family refusal rates."
There are 6,000 patients on the kidney waiting list but only about 1,800 transplants were carried out in the UK last year.
Organ transplant expert Professor Andrew Bradley, of Addenbrooke's Hospital, Cambridge, said without clear guidelines for surgeons they were unlikely to ignore the wishes of relatives who objected strongly to donation.
British Transplantation Society trustee Dr Anthony Warrens urged the development of a system that would help grieving families deal with the difficult decision of whether to agree to the use of an organ.
The HTA is the regulatory body for the Human Tissue Act which came into force on 1 September.
An HTA spokesman said: "We have put systems and guidance in place so that professionals have confidence they are acting within a clear regulatory framework. As a result we hope that public confidence will increase.
"We believe that a beneficial effect of the Act will be an increase in organs available for transplantation. Anything that helps this to be implemented, within the legislation, is welcomed by us."
The report also calls for an increase in efforts to identify suitable donors and transplant patients, and more surgeons to be trained.
It recommends a rise in donations from people whose heart has stopped beating which has only recently been made possible by advances in technology.
The law in Scotland is covered by the Human Tissue (Scotland) Act which also came into effect on 1 September.