SINGAPORE, May 15 (Reuters) - Singapore will inaugurate Lawrence Wong on Wednesday as its new prime minister and fourth leader since independence six decades ago, completing a carefully calibrated power transfer designed to guarantee continuity in the wealthy city-state.

Wong, 51, comes from among a crop of so-called "4G" leaders, a new generation of politicians hand-picked by the long-ruling People's Action Party (PAP) to take over the reins of the key Asian trade and financial centre.

Wong will retain his current position as finance minister and takes charge of a country led for two decades by Lee Hsien Loong, the 72-year-old son of Lee Kuan Yew, the founder of modern Singapore who stayed in politics until his death in 2015.

The succession has been long coming, with Lee's plans of stepping down before he turned 70 upended by the pandemic, and by a transition fumble when his anointed successor unexpectedly ruled himself out of the running in 2021.

Wong's inauguration will take place on Wednesday evening.

When the date for the handover was announced last month, Wong said he accepted the responsibility "with humility and a deep sense of duty" towards Singapore and its 5.9 million people.

"Every ounce of my energy shall be devoted to the service of our country and our people," Wong pledged in a video on his social media accounts.

STABLE POLITICS

Wong rose to prominence in 2020 as co-chair of the pandemic taskforce and was named Lee's successor in April 2022 after a series of consultations between the political leadership and Wong's peers.

He was promoted to deputy prime minister and led a high-profile public consultation exercise to chart a "social compact" between the government and the people on dealing with issues like sustainability, inequality and employment.

Wong made a very minor cabinet reshuffle on Monday, promoting the trade minister to become his deputy, noting that continuity and stability were key considerations. He has pledged a bigger reshuffle after an election due by next year.

Lee will remain in Wong's cabinet as senior minister, as former Singapore prime ministers have done, preserving the political clout of the long-serving Lee family.

His father stepped down as leader in 1990 and stayed on in the cabinets of his successors for 21 years, initially as senior minister then as "minister mentor" in his son's government.

In his final major speech last week, Lee urged the people to rally behind Wong and emphasized that Singapore's stable politics had enabled long-term planning.

"As I prepare to hand over Singapore in good order to my successor, I feel a sense of satisfaction and completeness," an emotional Lee told the crowd.

(Reporting by Xinghui Kok; Editing by Martin Petty)