Helen Clark no longer UN front-runner

SYDNEY, AUSTRALIA - FEBRUARY 22:  Helen Clark, ambassador of the United Nations development program attends the G20 Finance Ministers and Central Bank Governors official group photo, on February 22, 2014 in Sydney, Australia. This event is the first major G20 meeting under Australia's presidency in 2014.  (Photo by Lisa Maree Williams/Getty Images)

Helen Clark is no longer one of the front-runners in the race to be the next Secretary-General of the United Nations.

Reports from New York say the former prime minister didn't do well in the first secret ballot held by the Security Council to whittle down the 12 candidates.

It's being widely reported Miss Clark ended up in sixth place, right in the middle of the pack.

According to results seen by Reuters after the first secret ballot on Thursday, former Portuguese prime minister Antonio Guterres is the front runner, followed by former Slovenian president Danilo Turk.

Irina Bokova of Bulgaria, director-general of UN cultural organisation UNESCO, came in third, edging out former Serbian foreign minister Vuk Jeremic and former Macedonian foreign minister Srgjan Kerim, who tied for fourth.

Former prime minister Kevin Rudd has not placed in the top 12 candidates. Mr Rudd has been lobbying Canberra to support his candidacy as well as the key members of the UN Security Council.

The 15-member council will hold a series of secret ballots, until it reaches a consensus on a candidate it can recommend to the General Assembly.

In the process, low-ranked candidates are expected to withdraw until there just a few front-runners left.

The 193-member UN General Assembly this year has sought to lift a veil of secrecy that has surrounded the election of the UN chief for the past 70 years by requiring public nominations and holding campaign-style town hall events with each candidate.

Ultimately, the five nations that hold a veto on the Security Council - the United States, Britain, France, Russia and China - have to agree on a candidate and there is no requirement for them to pay attention to the popularity of candidates with the General Assembly.

Secretary-General Ban Ki-moon steps down at the end of the year and the council hopes to agree on a candidate by October.