Cristina Fernandez de Kirchner has consistently led the opinion polls. Argentines have been voting for a new president to succeed Nestor Kirchner, with his wife Cristina Fernandez de Kirchner seen as the clear favourite . Opinion polls suggest Mrs Kirchner could win enough votes to avoid a second round run-off next month. Her main rivals are a former beauty queen, Elisa Carrio , and Mr Kirchner's ex-Economy Minister Roberto Lavagna . Mr Kirchner has governed for the past four years, but surprised the nation by deciding not to seek a fresh term. Polling was extended by one hour in some parts of the country to 1900 local time (2200 GMT) to accommodate a late rush of voters. Besides a new president, voters were choosing eight provincial governors, a third of the Senate and about half of the Chamber of Deputies.