SOCIAL workers who claim they are being discriminated against are planning a campaign for higher salaries. Unionists called for better laws to protect workers in their fight for benefits and the right to protest. More than 300 social-work assistants have complained about pay discrepancies between them and senior welfare workers. Their maximum pay is $20,955 a month compared to $21,940 for senior welfare workers. Lai Wing-shing, chairman of the Social Work Assistant Branch under the Hong Kong Chinese Civil Servants' Association, said the revised pay which took effect on April 1 belied the principle of pay-for-the-job. Mr Lai said: 'Our post requires higher qualifications, a social work diploma. But the welfare workers are only certificate holders. We are more professional. How come we get less?' He said they would start putting up posters on Monday saying 'Professional social workers paid less than non-professional social workers' and 'The SWD discriminates against social workers' in more than 100 offices, including hospitals, family services and community centres and rehabilitation workshops, employing social work assistants. The department told the union 'the management will not be responsible for the wear and tear of the posters arising from normal cleansing of the offices', which Mr Lai described as a threat. Ng Sze-long, executive secretary of the Hong Kong Confederation of Trade Unions, said protesting workers in Hong Kong did not have rights and called for legislation similar to that in other countries so workers could express their discontent.