The Independent understands that officials from the department for business, energy and industrial strategy (BEIS) are keeping a close eye on the pilot programme and have already met the study's organisers to find out more.
A group of civil servants from BEIS discussed the design of the project and how the policy of cutting working hours with no loss of pay would work in practice.
But the government has said it has "no plans" to introduce a four-day week nationally, and that adopting reduced working hours would be down to the "individual choice" of businesses and workers.
In a letter to the organisers on behalf of Business Minister Paul Scully, a BEIS official said: “The government is committed to supporting individuals and businesses to work flexibly.
"While a four-day working week may work well for some workers and employers, the government does not believe there can be a ‘one size fits all’ approach to work arrangements.”
This month more than 3,300 workers at 70 UK companies, ranging from a local chip shop to marketing and finance firms began testing a four-day week with no loss of pay.
The six moth pilot – organised by 4 Day Week Global in partnership with the think-tank Autonomy, the 4 Day Week Campaign, and researchers at Cambridge University, Oxford University and Boston College – is the largest of its kind in the world.
Following the meeting with BEIS officials, Joe Ryle, the director of the 4 Day Week campaign, told The Independent: “It's very encouraging that the government are keeping a close eye on the UK's four-day week pilot.
“Politicians in Westminster across all parties can no longer ignore the growing momentum across British society for a four-day working week.
“The four-day week with no loss of pay is the future of work and can bring many benefits to the economy, productivity and crucially to the well being of workers.
“We're long overdue an update to working hours and it's an idea whose time has come.”
Asked about the meeting, a government spokesperson said: “There are no plans for the government to mandate a four-day working week.
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“Instead, our approach is guided by individual choice so that individuals and employers across the UK can work out the best working arrangements for themselves.”
An earlier trial of dramatically reduced working hours in Iceland was judged by researchers to be an “overwhelming success” and it has since seen some local trade unions negotiate permanently reduced hours.
The study found increases in worker productivity often made up for reductions in time spent at work, and that workers are significantly happier and healthier.
In Britain, the last Labour leadership explored the idea of gradually moving workers towards a four-day week, but the idea has not been retained under Keir Starmer.