MSPs passed the
Criminal Cases Bill
unanimously after its final parliamentary scrutiny on 20 June 2012.
The first part of the legislation intends to close a loophole where prisoners serving life sentences can apply for release on parole earlier than those serving fixed-length terms.
The Scottish government's proposals in the first part of the bill were in response to the decision of the High Court of Judiciary in the case of Petch & Foye v HM Advocate.
In 2011 rapist Robert Foye and paedophile Morris Petch challenged the way their minimum sentences had been calculated and saw them halved.
Under the legislation, the courts will regain powers to set the "punishment part" of sentences, which offenders must serve before being able to be considered for parole.
The bill also contains measures to officially permit publication of key information about the case of convicted Lockerbie bomber Abdelbaset al-Megrahi.
Justice Secretary Kenny MacAskill said the bill was a "small, important but complex bit of legislation which does take time to fully understand".
He accepted that the first part of the legislation had come in for some criticism on the grounds the provisions were too complicated.
Mr MacAskill said: "We accept that the provisions are complex, but we do not think they are unnecessarily complex."
He went on to say: "Our task in this bill is solely to resolve the Petch & Foye anomaly."
"As a Government, we wanted to act quickly and appropriately to address the problem raised by the judgment and ensure that people can have confidence in the sentencing of the most serious offenders."
The second part of the bill was introduced to be as open and transparent as possible about all aspects of the Lockerbie atrocity, but was drafted in general terms to be able to apply to potential future cases, said Mr MacAskill.
Scottish Labour community safety and legal affairs spokesperson Jenny Marra said her party would support the bill, but called on the government to monitor the introduction of the measures in the first part of the bill.
Ms Marra said the legislation was "difficult to comprehend and its outcomes difficult to predict" and stressed it was essential the "justice system has to be, and must also be seen to be, fair and comprehensible".
The need for the second part of the bill had been overtaken by the publication by the Sunday Herald of the statement of reasons for the abandoned appeal by Al Megrahi, said Ms Marra.
Scottish Conservative MSP Margaret Mitchell also said her party would back the bill, but said the new rules added to the complexity, described as tortuous and unintelligible to lawyers.
Ms Mitchell also called for the government to end automatic early release.
The final stage proceedings began with a number of amendments from the justice secretary which were all passed unanimously.