Senator Dan Boyle is expected to be elected Green Party chairman when nominations for the key position close today.
Four other candidates were in the running for the post, which was vacated when the John Gormley succeeded Trevor Sargent as party leader last month.
The other hopefuls are TD Paul Gogarty, Cllr Bronwyn Maher, Dr John Barry and Dublin party worker Phil Kearney.
Ballots were posted out to voting party members on October 1st.
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Mr Boyle lost his Dáil seat in May and later helped negotiate the programme for government with Fianna Fáil. He was nominated to the Seanad by the Taoiseach.