THE change in the composition of the New Territories Northwest constituency has dampened the chances of victory for the Democratic Party, candidate Zachary Wong Wai-yin has claimed. Faced with challenges from his long-time rival Tang Siu-tong, Mr Wong, a 37-year-old welfare worker, predicted that the battle would be a tougher one for his party. The main reason, he said, was that many constituents were drawn from the rural area where Mr Tang's power base lies. At present, Yuen Long rural area constitutes about one-third of the 110,000 voters in the New Territories Northwest constituency. 'Because of the high mobilisation power within the rural community, the turn-out rate there is usually higher than average,' Mr Wong said. 'In this sense, the rural faction will have a bigger say in the results.' The pair have been embroiled in three battles for the Yuen Long Legislative Council seat since direct elections were introduced to the law-making body in September 1991. Both were defeated at that time, but in a by-election in December 1991, Mr Wong ousted Mr Tang with a tally of 21,559 votes to 18,858 votes. The latter eventually made his way to the Legislative Council in the 1992 by-election caused by the death of Democrat Stephen Ng Ming-yum. The Democrat attributed the party's previous support partly to the housing estates in the constituency where voters were more likely to accept liberal ideas. Citing the results of the last district board and regional council elections, Mr Wong said most of the constituency had fallen into the hands of the conservative rural faction and the pro-China sector. 'It is apparent that the pro-China faction is forming a united front with the rural faction,' he said. 'I am the only councillor surviving in the constituency from the party; my position is rather dangerous.' Although Mr Wong was confident that he could defeat Mr Tang in the housing estates in Tin Shui Wai, this might not make up for his losses in the rural areas.