JOHANNESBURG (Reuters) - South Africa's top public health worker union said on Wednesday it wanted a 15 percent across-the-board wage increase and would begin a series of protest marches over poor government services this week. National Education Health & Allied Workers Union said in a statement there was a public health "crisis" in Africa's most developed economy because of government outsourcing. The union also wants a 3000 rand ($265) housing allowance for its workers. (1 US dollar = 11.2794 South African rand)