The findings are the result of a Unison survey which has prompted the union to call for urgent action on race inequality in the public sector.
Only 11% of employers have set targets for the employment of ethnic minorities, despite 36% admitting they are under-represented.
Nearly every employer has an equal opportunities policies, 87% of which review them regularly, and nearly two thirds train managers in recruitment and selection. Just over a third extend this to all staff, but 59% admit they do not give training on the delivery of services to diverse communities.
Two thirds of organisations have reviewed policies in light of the report, but nearly half have not reviewed their service provision.
'Many employers recognise they must address institutional racism and the Stephen Lawrence inquiry has had an impact on employer sensitivity to the issue,' said Unison deputy general secretary Keith Sonnet. 'But translating policy into practice has not been as successful as it could have been.
'There is a surprising under-representation of black and ethnic minority workers in the public sector. We believe the public sector should be leading the way in making sure services and employment practices reflect the interests and needs of the communities they serve.'
Unison's recommendations include proposals that employers set targets for recruitment which reflect the demographic area from which staff are drawn.
The survey of fire, police, local and health authorities, as well as further and higher education institutions and the utilities, received more than 440 responses.