Legislation to update the public's right to scrutinise how taxpayers' money is spent is expected to be passed at Holyrood.
The Freedom of Information (Amendment) Bill is designed to bring the original decade-old Act up to date with recent developments, but some MSPs and campaigners say it does not go far enough.
Scottish Information Commissioner Rosemary Agnew expressed "serious concerns" about some the Government's original proposals, particularly the plan to give absolute exemption to senior members of the Royal Family.
Speaking before the final reading of the Act, Ms Agnew said she is satisfied with some of the amendments brought forward at stage two. "The Scottish Government has responded by removing proposals for an absolute royal exemption, and requiring Ministers to report to Parliament every three years on their use of section 5 powers (designation of Scottish public authorities) and wider consultation with 'other appropriate persons' (not just the authorities being considered)," she said.
Ms Agnew also welcomed Deputy First Minister Nicola Sturgeon's commitment to extend freedom of information law to arms-length external organisations (Aleos) "in early course", although they are unlikely to be included in the current Bill.
The rise of Aleos, where councils set up external companies to run public services, has been a matter of concern for some MSPs and officials in recent years, particularly because of their lack of public scrutiny.
Labour MSP Elaine Murray will again attempt to convince MSPs to back her amendment to see Aleos included in the FoI (Amendment) Bill today. Her amendment was withdrawn at stage two after a sceptical response by Deputy First Minister Nicola Sturgeon and a lukewarm reception by majority SNP MSPs.
Dave Moxham, general secretary of the Scottish Trades Union Congress, said: "We support the Campaign for Freedom of Information in Scotland in arguing that FoI rights must be maintained and extended, not curtailed and reduced. With the estimated number of arms-length bodies in Scotland delivering public services now exceeding 130, the need to know how public money is being spent is critical for transparency and accountability."
Liberal Democrat leader Willie Rennie called on Ms Sturgeon and her SNP colleagues to support moves to broaden the public's access to information. "Changes to how local authorities deliver public services have had a real impact on the public's right to information," he said.
A Scottish Government spokesman said: "Scotland already has the most robust Freedom of Information regime in these islands. "It is this Government's aim to ensure that this continues, and that we have a transparency system that sets an example for other nations to aspire to."