A nationwide union of nurses and medical workers began voting Monday on whether to strike over a pay raise, union officials said, in a move that could put more strain on public health services amid an ongoing walkout by trainee doctors.The Korean Health and Medical Workers' Union, which has some 30,000 nurses and medical workers at 62 hospitals as members, has demanded a 6.4 percent increase in wages, but hospitals are unlikely to accept the demand because their businesses have been hurt by the walkout.If the union votes to strike and fails to narrow differences in negotiations with hospitals, it will go on strike Aug. 29, according to union officials.About 12,000 trainee doctors have left their worksites since late February in protest of the government's plan to boost the number of medical students.A union official said the union is unlikely to narrow gaps with hospitals because "situations at hospitals are very difficult as (trainee doctors) refuse to provide medical treatment and the bed utilizati on rate is so low."Even if the union decides to strike, nurses and medical workers in essential services will continue to work in accordance with the law, union officials said.Source: Yonhap News Agency