Even in the public sector, where equal pay monitoring is a statutory requirement, the study finds only 43% complete audits, with many of these described as "ticking the bureaucratic box rather than as part of an underlying effort to advance gender equality".
Dianah Worman, CIPD diversity adviser, said: "The Government faces an uphill struggle in its efforts to change employer attitudes to closing the gender pay gap."
Under the provisions of the Equality Bill - due to be passed early next year - the Government is considering forcing companies with more than 250 staff to report their gender pay gaps by 2013 if too few of them are doing it voluntarily.
According to KPMG, employees experience better pay reviews when they work for companies that do report pay gaps.
Ingrid Waterfield, KPMG head of reward, said: "Employers should investigate pay structures from the perspective of fairness and equality whether or not legislation is introduced. Leading businesses will examine their pay gaps not because of government, but because they understand the impact to their reputation and possible legal damage of not getting it right.