Proposals to legalise assisted suicide are complex and confusing in places, according to the Faculty of Advocates.
The Scottish Bar has raised concerns over some of the technical and legal aspects of the Assisted Suicide Bill.
The Bill is being taken forward by Green MSP Patrick Harvie on behalf of former independent MSP Margo MacDonald, who died in April following a long battle with Parkinson's disease.
It contains proposals to allow those with terminal or life-shortening illnesses to obtain help in ending their suffering.
In a submission to the Scottish Parliament, the faculty has stressed that if assisted suicide is to be legalised, clarity in the legislation is "imperative".
It states: "If Parliament is to pass legislation to protect persons from what would otherwise be the legal consequences of assisting another person to commit suicide, the faculty considers it is important that such legislation is clear, readily understood (and not just by lawyers), that key terms are well-defined and not open to a variety of interpretations, and that the penalties for breach of the requirements of the legislation are spelled out.
"Otherwise, persons wishing the protection of the legislation will be unclear as to whether their acts are protected and may render themselves liable to prosecution for serious crimes or subsequent review of their conduct in a civil court.
"The faculty considers that the Bill as currently drafted may not achieve these essential goals."
The Bill represents a second attempt to legalise assisted suicide in Scotland, following a previous Bill taken forward by Ms MacDonald in 2010.
Supporters and campaigners say the new proposals are better and contain safeguards to address the concerns of those opposed to it.
It now contains an ''early warning'' aspect, whereby anyone over the age of 16 can inform their GP of their support in principle for assisted suicide.
Any requests to GPs must be backed up by a second professional opinion and followed by a 14-day ''cooling-off'' period.
This process is then repeated again with a second request, after which one of the doctors concerned supplies a licensed facilitator with a prescription to enable assisted suicide to take place.
This facilitator, or ''friend at the end'', has no relationship with the patient and is given the task of collecting the prescription and agreeing the process of assisted suicide.
The faculty said: "It is not clear whether the facilitator requires to remain with the person until he dies.
"The facilitator is also to provide such practical assistance as the person wishing to commit suicide reasonably requests.
"The faculty notes the tension between this provision and the requirement that the person's death be his own deliberate act.
"The Bill does not specify the means by which a person might commit suicide.
"Section 19 seems to envisage that a person would commit suicide by ingesting drugs.
"The faculty is unclear from the wording of the Bill whether or not it is intended to extend protection to the use of other methods by which a person might commit suicide."
The Bill contains no sanctions or penalties for contravention of its provisions, the faculty added, while there is a lack of detail about record-keeping by the various people involved and inspection of records to prevent abuse.
"The faculty considers that, if assisted suicide is to be legalised...clarity is imperative," it said.
The faculty neither supported nor opposed the policy of assisted suicide itself.