The Scottish Government is to review the Scottish Business Pledge scheme to encourage more firms to sign up.
The programme was launched in May 2015 to promote fair work practices, including paying the living wage, and boost productivity.
So far, 450 firms have joined, employability and training minister Jamie Hepburn told MSPs.
To sign up to the pledge, a company must commit to paying the living wage of £8.75 an hour and to at least two other criteria, ranging from not using zero hour contracts to paying bills promptly and creating opportunities for young people.
Opposition politicians have criticised the level of interest the initiative has generated, with 371 firms signed up by the start of June last year, equivalent to 0.2% of Scotland’s registered business base.
Speaking in a Holyrood debate, Mr Hepburn said: “Today I’m announcing a short review of the business pledge focusing on securing greater business buy-in and impact.
“Over the summer we will work with current pledge companies, the main business organisations and the wider business community to explore barriers to making a commitment to the business pledge and indeed ways the pledge might evolve.”
He also announced Scottish Government funding to support trade unions to promote fair work would continue for a third year, with £250,000 and £100,000 to go to the Scottish Trades Union Congress for fair work leadership and equality programmes.
Mr Hepburn said Economy Secretary Keith Brown would bring forward a fair work action plan before the end of the year and invited other parties to contribute.
Conservative Dean Lockhart said: “If the Scottish Government is serious about delivering fairness it needs to start addressing some of the hard economic realities.
“We have a stagnant economy, an increasing skills gap, declining education standards, inadequate training with 160,000 college places cut and not replaced.
“We have increasing failure rates for small businesses and workers in Scotland, have the lowest wage growth in the UK and the lowest disposable incomes, but they are paying the highest level of income tax in the UK.”
Labour’s Jackie Baillie criticised the working practices on public-sector projects, saying some staff had been on “bogus self-employment contracts” which involved charges of £100 by umbrella companies to receive their wages.
She claimed the Scottish Government had employed some agency workers for five years “on lesser terms and conditions than civil servants doing exactly the same job”.
She said: “It is breath-taking hypocrisy for the SNP government to pretend to champion fair work whilst engaging in some of the practices they rightly condemn.”
Green co-convener Patrick Harvie scored the Scottish Government at six out of 10 for its efforts to improve working practices, saying: “It’s a pass mark but it needs to go a lot further.”