A TIGHT vote is expected today on the attempt by the Liberal Party's Mr Allen Lee Peng-fei to block a United Democrat motion urging a referendum on the territory's future electoral arrangements. Mr Lee, the most senior Legco member, will propose adjourning the debate immediately after United Democrat Mr Szeto Wah moves his motion. The Liberal Party said it did not believe today was the right time to discuss the issue. It supported a referendum only on whether the public wanted convergence if Britain and China failed to reach agreement. Legislators were divided over whether the debate should proceed on the eve of long-awaited Sino-British negotiations on the 1994/95 electoral arrangements in Beijing. Those who supported the stalling attempt by Mr Lee said such a debate would be harmful to the atmosphere for the talks. Elected legislator Dr Tang Siu-tong, who opposed holding a referendum to decide Hongkong's political development, said legislators should not go ahead with the debate. Regional Council representative Mr Gilbert Leung Kam-ho said the debate on Mr Szeto's motion would not be constructive. Other legislators said Mr Lee's attempt would set a bad precedent of suppressing any debate on a motion legislators found unfavourable. Meeting Point's Mr Fred Li Wah-ming said legislators were free to express their views on the motion but should not try to make use of the procedures on moving motions to prevent discussion. His view was backed by the chairman of the Association for Democracy and People's Livelihood, Mr Frederick Fung Kin-kee, who said: ''If you disagree with Mr Szeto's motion, you can amend it or even vote against it.'' Directly elected legislator Mr Andrew Wong Wang-fat, described the attempt to block the debate as meaningless and said the motion would eventually be put back on the agenda even if the debate was called off this time. Miss Emily Lau Wai-hing also said the debate should go ahead. ''Even if the motion [moved by Mr Szeto] is carried, the Government may not hold a referendum,'' she said. Mr Jimmy McGregor thought it appropriate to hold a referendum on future constitutional development, saying ''it will be very useful to have the opinions of the people of Hongkong on this important issue''.