Australian ruling Labor Party toppled its leader Kevin Rudd in a shock intra-party ballot Thursday morning and Rudd's deputy, the challenger Julia Gillard became Australian first female prime minister.

Julia Gillard was elected unopposed leader of the ruling party in the ballot. Rudd's approval rating has been declining over such issues as the controversial super mining and resources tax, climate change and the mishandling of smuggled refugees. His party had lost faith that he could win a second term at the national elections due within months.

Rudd's disapproval rating hit record levels of 55 percent in a poll released on Monday. Australian Workers Union National Secretary Paul Hawes also said that he no longer supported Rudd.

With the support of key powerbrokers of the ruling party, Gillard decided to challenge Rudd's leadership.

Rudd, Gillard and some senior cabinet members -- former Treasurer Wayne Swan, Finance Minister Lindsay Tanner, Defense Minister John Faulkner and Minister of Infrastructure Anthony Albanese had caucus talks. After hours of closed-door meeting with Gillard and senior ministers, Rudd called the shock ballot Wednesday evening

The direct trigger of Rudd's quit was the forceful implementation of the excess resources tax in early May this year. The government and the industry could not establish effective communication and consultation, making the resource tax arduous.

Many have also complained about the Rudd approach of doing things, termed it as "dictating."

At a press conference on Thursday morning, Kevin Rudd, accompanied by his family, was emotional, choking several times. " I was elected by the people of this country to bring back a fair go for all Australians and I have given my absolute best to do that." He thanked the Australian people for the trust extended to him.

Gillard, 48, made history as the first female Australian prime minister whom critics said is more approachable, more willing to consult with others, which the Labor Party thinks will help them win the federal election this year.