Up to 4,000 Hospital Authority staff have been underpaid for years and are on terms less favourable than those hired earlier, unionists said yesterday. About a dozen members of the Hong Kong Hospital Staff Rights Union held a demonstration outside the authority's headquarters to protest against the pay policy. The union, which represents general service assistants (GSA) and technical service assistants (TSA) who have worked for the authority since 2000, said that although its members were converted from contract employees to permanent staff in 2006, they were paid less and enjoyed fewer benefits. An entry-level general service assistant was paid HK$7,000 with no allowances but a person employed as 'Workman II' under the old system, with the same duties, was paid HK$12,000, union chairwoman Chan Choi-chun said. 'This is unfair. Although the titles are different, we do the same tasks. Why are GSAs paid less?' Chan said, adding that workmen were eligible for the authority's general pay rises, but salary increases for service assistants were based on performance. 'We are very unhappy because our jobs are not stable at all,' she said. The union is demanding that the authority offer its members the same benefits as permanent staff employed under the old system. An authority spokesman admitted that staff employed at different times were paid under different systems. 'This does not only happen among GSA and TSAs, but also other posts in the authority' and in the private sector, he said. He added that when authority staff took a general pay cut in 2002, 2004 and 2005, the salaries of the assistants remained unchanged. The authority would consider the union's proposal, he said.