The UK Government wants to use its Immigration Bill, which has just passed a second reading in the House of Lords, to make it harder for those facing deportation to claim their right to a family life is threatened.
However, the Law Society of Scotland believes the Bill could tie the hands of judges, rather than allow them to use their own discretion to decide the merits of cases.
The body, which represents all Scottish solicitors, has asked peers to reconsider this part of the Bill.
Michael Clancy, its director of law reform, said: "We do not agree with proposals to take away from judges the ability to make just decisions in immigration cases, which involve the right to respect for private and family life.
Home Office minister John Taylor, Lord Taylor of Holbeach, defended the Bill as strengthening rights.
Speaking in the House of Lords, he said: "We can ensure that serious criminals will be deported and that those deportations will be subject to less delay. That will not damage human rights but restore balance. It will address the erosion of public confidence in our laws."