Plans to move to an opt-out system for organ donations could boost the rate of donations by almost a third, MSPs have been told.

Labour MSP Anne McTaggart told Holyrood's Health Committee that her Transplantation Bill was "absolutely" necessary as the current opt-in arrangement "is not working".

The legislation proposes a move from a system in which people have to actively join the NHS Organ Donation Register to a ''soft'' opt-out approach in an effort to tackle a shortage of organs.

Ms McTaggart told the committee: "We do need to increase transplantation.

"The first-quarter figures for this year show that we are heading for an even bigger decrease in deceased donor rates of 10%.

"We have to do something different, whatever we are doing just now is not working.

"International evidence shows us that a 25% to 30% increase will happen if we move to a soft opt-out system."

Under the plans, organs and tissues could be removed from an adult after death if they had not registered or expressed an objection during their lifetime.

Families would also be consulted on the death of a loved one to establish any objection that had not been registered.

Dr James Cant, director of British Heart Foundation Scotland, highlighted that 46% of families had refused a donation in 2014/15 because they did not know what their relative's wishes were.

He said: "The conversations are not taking place and the rate of family refusal is actually on the increase at this point in time.

"The single most important thing that this legislation could do would be to change the framework to have the default position that there would be an assumption that people had opted into the system, because otherwise we're relying upon conversations which aren't taking place currently or conversations which do take place in the calm of the here and now which then don't translate into actions when we actually have the death of the person."

Labour MSP Rhoda Grant raised concerns the change could cause conflict between between medics and relatives.

She said: "Do you foresee a situation where a family being asked if they knew about their loved one's wishes said 'no, but for religious reasons or whatever reasons I object to this happening?'

"I can't foresee a situation where a clinician would then go against a family's wishes if that was going to cause them real distress."

Lindsay Paterson, policy manager for the Royal College of Physicians of Edinburgh, said: "At a time when it's very stressful, when for example there's been a traumatic accident, something which is totally unexpected, a family who are visiting a patient potentially at the end of their life will be obviously very upset and conversations around organ donation have to be very sensitive.

"I think at a time when a family are potentially very stressed, everything is happening very quickly, a clinician who is speaking to that family and who is caring for the patient would find it very difficult to try and go against the wishes of the family at that particularly distressing time."

Dr Sue Robertson, a member of the British Medical Association (BMA)'s Scottish council and renal physician in Dumfries, said a soft opt-out system could make the conversation easier for affected families, particularly in the wake of public debate around the legislation.

She added: "There are some situations that we feel would cause the family undue distress and in that situation we feel the legislation should allow us not to go forward."