SINGAPORE, May 15 (Reuters) - Singapore's Lawrence Wong, who becomes on Wednesday the wealthy city-state's first new prime minister in 20 years, took to Tiktok in the years before to engage with citizens, singing, playing guitar and posting on issues such as mental health.

Behind that affable online personality is a man colleagues say is an able technocrat who embodies a generational shift in leadership yet exemplifies continuity in a nation ruled by his People's Action Party (PAP) since before independence in 1965.

Wong is "quite conservative" and "prefers incremental over radical change", said Donald Low, a former colleague who is now a public policy specialist at the Hong Kong University of Science and Technology.

"In that sense, Lawrence as PM probably wouldn't be all that different ... the emphasis would be on continuity, rather than radical change," said Low, adding that did not expect major changes with Wong at the helm.

Wong, 51, was most recently in the public eye for delivering clear explanations of the strict COVID-19 measures the nation of 5.9 million adopted since 2020, when he was co-chair of its pandemic management effort.

During a long career in the civil service before that, he worked from 2005 to 2008 as principal private secretary to outgoing prime minister Lee Hsien Loong before entering politics in 2011.

He chaired the central bank among other roles, and will retain the finance portfolio after becoming prime minister.

Most in the Asian financial hub appear, by a slim majority, to approve of Wong's ability to do the job.

He was rated competent by 53% of 1,025 respondents to a YouGov poll in April, though just 40% said he was trustworthy and 37% called him likeable.

That compares with approval of just 38% among Americans for U.S. President Joe Biden in a Reuters poll.

OPEN BUT "REALISTIC"

Though Wong is widely seen as a status quo-leader, colleagues says he expressed openness to new ideas in the past, in a political landscape dominated not only by a single party but where the Lee family loomed large for more than 50 years.

PAP founder Lee Kuan Yew led the country from 1959 until 1990 but stayed in cabinet till 2011, and his son, the outgoing prime minister, took office in 2004.

Irvin Seah, head of DBS Bank's Asia Insights Office, said Wong was always open to ideas and opinions in interactions during Seah's time as an economist, even sensitive issues, and was not the type to surround himself with "yes men".

Criticisms of Wong are few, as he kept a fairly low profile while a minister, before the pandemic spotlight.

"He is realistic, but not cynical as a political leader," said Gillian Koh, a researcher in governance and economy at the Institute of Policy Studies, who saw Wong as having a grasp of a wide range of policies, and as being decisive and even-tempered.

Koh pointed to his remarks after the last general election in 2020, when Wong said it was clear citizens wanted diverse voices and political opposition.

Wong added that the party would have to approach every general election as one in which it was seeking to form the government, rather than taking the mandate for granted.

CHALLENGES AHEAD

Wong's challenges as prime minister would be external, said Low, the former colleague, with rivalry between the United States and China shaping as a particular test, and not only because Wong had relatively less exposure to foreign affairs.

While Wong and the rest of the party's leadership might prefer not to choose between Beijing and Washington, he said many in the rank-and-file might prefer a more pro-China stance.

"Managing this intra-party tension would be a major test of Lawrence as party leader."

Wong would also have to help citizens achieve their dreams in an advanced economy that has outpaced an older model of looking to other countries for development strategies, Low added.

"Singapore is now at the leading edge of development and it will have to chart its own future."

Little is known of Wong's personality beyond the facts that he is a music fan and a dog lover, prompting one analyst to call for more details of his leadership plans.

"So far, Wong has not laid out his political vision or why Singapore should support it," said Chong Ja Ian of the National University of Singapore, pointing to his guitar-playing on social media.

"For me, I think Singapore needs a prime minister right now, not a cover band." (Reporting by Xinghui Kok; Editing by Clarence Fernandez)