SEOUL - The liberal politician expected to succeed disgraced Park Geun-hye as the Republic of Korea's next president could significantly soften Seoul's stance towards the Democratic People's Republic of Korea and possibly delay deployment of a US missile-defence system.

A Constitutional Court on Friday dismissed Park from office after upholding her impeachment over a corruption scandal involving chaebol, the family-run conglomerates that dominate Asia's fourth-biggest economy, and which could also face reform under a liberal leader.

Hundreds of thousands of South Koreans took to the streets on Saturday night for a last, festive candlelight rally to celebrate Park's ouster.

Park left the presidential palace on Sunday evening, two days after the country's Constitutional Court removed her from office over a massive corruption scandal.

ROK television showed Park's motorcade leaving the Blue House and heading for her private home in southern Seoul, where hundreds of police officers, reporters and supporters were gathered in anticipation of her arrival.

A presidential election will be held by May 9, and opinion polls suggest people will opt for change by sending a liberal to the presidential Blue House, ending nine years of conservative rule.

The front-runner is Moon Jae-in, a human rights lawyer who was a top aide to former president Roh Moo-hyun, an advocate of a "sunshine policy" of engagement with the DPRK.

Moon has criticized the two former conservative presidents - Park and her predecessor, Lee Myung-bak - for derailing the progress made in ROK-DPRK relations during the previous liberal administrations.

He calls for a "two-step" approach on the DPRK, with talks leading first to "economic unification" and ultimately "political and military unification".

Speaking to reporters recently, Moon invoked his old boss, Roh, and Roh's predecessor, Nobel Peace Prize winner Kim Dae-jung, the architect of the "sunshine policy", as inspirations behind his bid for the presidency.

The two former liberal presidents both held summits with the DPRK's then-leader, Kim Jong Il - the only such meetings ever - promising reconciliation and initiating joint projects including the Kaesong Industrial Complex and tours to Mount Kumgang in the DPRK.

Both were suspended under conservative administrations.

Moon said the ROK should resume operations at Kaesong - where ROK companies operate factories with DPRK workers on the DPRK side of the border - regardless of Pyongyang's nuclear ambitions.

Republic of Korea ex-leader Park Geun-hye greets supporters as she arrives at her home in Seoul on Sunday.Reuters