Singapore Prime Minister Lee Hsien Loong will step down next month and his deputy Lawrence Wong will take over, the second non-member of the Lee family to lead the wealthy nation.

"I will relinquish my role as Prime Minister on 15 May 2024 and DPM (Deputy Prime Minister) Lawrence Wong will be sworn in as the next Prime Minister on the same day," Lee said on social media on Monday.

"I ask all Singaporeans to give Lawrence and his team your full support, and work with them to create a brighter future for Singapore."

Wong, who is also the finance minister, was chosen as Lee's heir-apparent in 2022 from a new generation of lawmakers from the People's Action Party (PAP) which has ruled uninterrupted since independence in 1965.

"I accept this responsibility with humility and a deep sense of duty. I pledge to give you my all in this undertaking," Wong said on social media.

The 51-year-old, US-educated economist is widely seen as a social media-savvy stalwart who effectively handled the Covid-19 crisis when he oversaw the government's pandemic taskforce.

The city-state was one of the first in Asia to quickly get back in the saddle as the pandemic eased in 2022, with business and tourism numbers picking up.

Mustafa Izzuddin, a political analyst with consultancy Solaris Strategies Singapore, said Wong was already well known in Southeast Asia and to the two major powers most important to the city-state, China and the United States.

"I think he brings a style of leadership that's more attuned to a different generation. I think the core principle of what Singapore is about will remain because it is a system that has worked for many years," he said.

"But I think his style may be maybe slightly different because he comes from a different generation."

Outgoing Premier Lee's father, Lee Kuan Yew, was Singapore's first prime minister when it became a sovereign nation after a brief, unsuccessful union with Malaysia.

In 1990, the elder Lee handed power to his deputy, former shipping executive Goh Chok Tong, who was initially considered a "seat-warmer" for the patriarch's son.

Goh, however, stayed on for 14 years before the younger Lee took over in 2004.

A general election has to be called by November 2025 but there is speculation it could take place this year.

In the previous election in 2020, the opposition showed its strongest performance since independence but hardly made a dent in parliament as 83 out of the 93 seats were won by the PAP.

The PAP's squeaky clean image was recently stained by scandals which saw two lawmakers resign and a minister charged with graft.

The Workers' Party, Singapore's main opposition party, has also suffered from scandals with two members resigning and its leader charged for giving false testimony before a parliamentary committee.