The majority (87%) of people asked admitted to working overtime hours, with many suggesting they're more likely to do so when working from home.
Katy Fridman, founder of flexible working platform Flexible Working People, suggested working fathers being denied flexibility could be contributing to the higher rate of overtime.
Speaking to HR magazine, she said: "Whilst companies across the UK have been ripping up and rewriting their flex working rule books, research from Fawcett has shown that fathers' requests for flexible working are refused at twice the rate of mothers.
"If we aren't setting gender balance in the work environment then we are feeding the notion that men must work fixed and longer hours, which is exactly what is playing out here."
Data from the Office of National Statistics (ONS) published earlier this year however suggested that women were the ones working more overtime, clocking in 4.5 extra hours a week compared to 2.8 extra hours for men.
Fridman added: "It's really important that we don't confuse and reduce the notion of flexible working down to working remotely. If the culture of your business buys into presenteeism and overworking then this will lead to burnout, and reduced staff happiness, as the temptation to prove that you are working hard, will lead to overworking.
"Especially now that increasingly we are out of sight, we want desperately to not be out of mind."
Two thirds (67%) of people said they enjoy where they work, and people under 35 were more likely to say so.
A further 42% said they would be disappointed to return to working five days in the office.
Office Freedom surveyed 2,000 office workers across the UK.