(Adds union chief comments) BEIRUT, Jan 10 (Reuters) - Hundreds of Lebanese protesters gathered outside the Energy and Water Ministry on Wednesday as part of a Hezbollah-led campaign to topple the government and block its economic reform plans. "We don't want a tax hike, we want a wage hike," a banner carried by one demonstrator read. Soldiers and police cordoned off the ministry, in a Christian area of Beirut, as protesters arrived in minibuses. A similar protest took place at a Finance Ministry tax office on Tuesday. The demonstrations, so far thinly attended compared to the vast gatherings organised by Hezbollah and its allies in December, were called by the main labour union confederation and backed by the opposition to press a 41-day-old campaign to topple Prime Minister Fouad Siniora's government. Protesters have camped outside Siniora's offices in central Beirut since Dec. 1 to try to force him to cede veto power to the opposition in a unity government or call early elections. Siniora, who has Western and Saudi backing, has resisted those demands, instead announcing an economic reform package to be presented at an international donor conference in Paris. The Beirut government hopes the Jan. 25 conference, which U.S. Secretary of State Condoleezza Rice plans to attend, will bring billions of dollars of aid to an economy reeling from Hezbollah's July-August war with Israel. The reforms, which aim to boost growth and ease Lebanon's $41 billion public debt, include raising value-added tax and privatising the mobile telecom sector -- both rejected by the union confederation as damaging workers' rights. The opposition, led by the Iranian- and Syrian-backed Shi'ite Hezbollah, has pledged to organise daily protests near government buildings and facilities until Siniora gives way. "The conference or the paper (reform programme) do not intimidate us ... We are standing by your side, we are with you," union chief Ghassan Ghosn addressed a crowd of supporters waving the Lebanese red-and-white flag. "This paper will not pass, taxes will not be passed on to the Lebanese people. Let them look for taxes in the safes of wealthy people, not in the pockets of poor people."