The Lord Advocate's appearances at Cabinet markedly increased following the Nationalists' landslide victory in 2011, leading to fears his role is becoming politicised.
Labour MSP Graeme Pearson said there was an "absolute" need to maintain a "separation of powers" between the executive and the legislative arms of government.
The Lord Advocate, currently Frank Mulholland, has a twin role heading the prosection service and acting as legal adviser to ministers. However, combining the roles has long caused concern for critics who believe there is an unhealthy overlap of political and legal functions.
In May 2007, days after becoming First Minister, Alex Salmond informed Parliament of plans for a historic move to depoliticise the Lord Advocate's role.
He said: "The involvement of the law officers in the political operations of government is, in my view, unnecessary and inappropriate, so I have decided that the Lord Advocate will not be a member of the Cabinet and will not normally attend meetings.
"That will emphasise the apolitical and professional role that the Lord Advocate and I have agreed is appropriate in the provision of legal advice to government."
Salmond said his reform was a "separation of powers" and a "clear division between the political and the judicial and between politics and the prosecution service".
The change was welcomed across the political divide, but figures obtained by the Sunday Herald show the Lord Advocate has regularly attended Cabinet since the First Minister's statement. In the SNP's first - minority - administration, post-holder Elish Angiolini appeared at Cabinet 28 times. However, since Mulholland took over in 2011, appearances have surged to 45 only two-and-a-half years into the term of office.
One insider said the rise could be explained by the SNP's historic win in 2011, which meant an independence vote became a certainty. Mulholland is expected to be a key figure in ensuring that the Government's prospectus for independence - laid out in a White Paper next month - is legally watertight.
Pearson said: "The figures reveal a stunning disregard on the part of Alex Salmond for his own declared intention to keep the Lord Advocate out of politics. The absolute need to maintain a separation of powers in this regard is being ignored at will by the SNP Government, a government imbued with a desire to centralise and control."
A spokesperson for the Scottish Government said: "Under the arrangements for Cabinet announced in 2007, and in keeping with their apolitical status, Lords Advocate now attend Cabinet on an ad-hoc basis when Cabinet is discussing a matter that has a legal aspect or concerns the Crown Office and Procurator Fiscal Service.
"This is different from previously, when Lords Advocate routinely attended all Cabinet meetings. Lords Advocate are no longer required to attend, and the occasions on which they have been in attendance account for around half of all Cabinet meetings since the new policy was announced."