The report, Age Over Beauty?, seen exclusively by HR magazine, is based on interviews with 1,000 employees and looks at discrimination faced due to age and gender.
It found that 10% of workers in companies with more than 50 staff or more face barriers due to their gender, compared to 1.3% in micro-businesses (between one and nine employees) and small companies (between 10 and 49).
Additionally, in micro-businesses and small employers the number who have witnessed age discrimination is almost zero, compared to 20% in medium-sized employers and larger.
Doyle Clayton partner Jessica Corsi told HR magazine HR issues can often arise when a company grows quickly from a small start-up to a larger organisation.
"Often in these circumstances it won't feel like you have time to focus on HR issues," she said. "Other growth issues such as finance will demand immediate attention and people issues may get left behind. It's a good idea to make sure processes and sound policies are put in place as early as possible."
Corsi also warned that discrimination can become a "self-fulfilling prophecy" during this period.
"If you've grown from a small business of fewer than 10 people, it can go from feeling like a family to something less personal," she said. "If one person starts to feel discriminated against in this environment, others may look at their situation and decide the same applies to them. If you're not careful things can go badly wrong very quickly."
Carter Backer Winter HR director Nicola Bell told HR magazine it is important to have "open, clear and transparent policies". She also encouraged companies to seek HR advice, even if they don't have the resources for a full-time HR department.
"You can get advice from an external consultancy," she said. "This can help get all the people issues consolidated. Sometimes it's better that all these things are in one place."
