"The new administration will usher in a new era of hope premised on a revitalizing economy, the happiness of our people, and the blossoming of our culture," Park said in an inauguration speech delivered to some 70,000 people gathered in front of the parliament for the ceremony.
Park, whose inauguration came on the heels of a widely condemned nuclear test by the DPRK, also sent a warning message to the unpredictable northern neighbor.
"North Korea (DPRK)'s recent nuclear test is a challenge to the survival and future of the Korean people, and there should be no mistake that the biggest victim will be none other than North Korea itself," Park said. "I urge North Korea to abandon its nuclear ambitions without delay and embark on the path to peace and shared development."
At the same time, she reaffirmed her pledge to seek a so-called "trust-building process" between the two Koreas to "lay the groundwork for an era of harmonious unification."
"Trust can be built through dialogue and by honoring promises that have already been made. It is my hope that North Korea will abide by international norms and make the right choice so that the trust-building process on the Korean Peninsula can move forward," Park said.
Observers have said the recent nuclear test significantly reduced wiggle room for Park, who appears willing to extend an olive branch only when Pyongyang complies with the very international regulations it has violated by developing nuclear programs.
Her first call after beginning her five-year term midnight Sunday was to Gen. Jung Seung-jo, chairman of the Joint Chiefs of Staff, a move designed to highlight her commitment to border security.
The 61-year-old daughter of late military strongman Park Chung- hee won the Dec. 19 presidential election, becoming the first-ever president to earn a majority of the popular vote since democratic elections were introduced here in 1987.
Park, a political veteran with the moniker "queen of elections, " acted as the de facto first lady to her father after her mother was assassinated by a DPRK agent and is credited with reviving the ruling party mired in corruption scandals.
She remains widely popular among older people nostalgic for rapid economic growth under the senior Park's 18-year authoritarian rule, while critics point to ruthless suppression of dissidents during his reign.
She replaced Lee Myung-bak, her political nemesis who beat her in the 2007 ruling party primary to win the presidential nomination.
Lee, who was constitutionally barred from running for re- election, returned to his residence in southern Seoul.
One of the immediate challenges facing the Park administration for now is forming the Cabinet, with opposition parties looking to foil some of the Cabinet nominations in the coming weeks.
The presidential office Cheong Wa Dae, to which Park returns for the first time in 33 years, also remains in disarray. Senior presidential aides have been named but are yet to be officially confirmed for their posts, while working-level staffers have not even been tipped.
Parliamentary confirmation hearings for the minister nominees are set to begin as early as Wednesday, but observers expect an administrative vacuum and bitter partisan fights down the road.
By Guylain Gustave Moke
Photo-Credit: Wikipédia: Park Geun-Hye