HONG KONG (AFP/REUTERS) - Carrie Lam's swearing-in as Hong Kong's new leader on Saturday (July 1) marks the culmination of the lifelong civil servant's career as she inherits a divided city concerned about China's encroaching influence.

Lam, 59, was widely seen as Beijing's preferred candidate when she was elected in March by a mainly pro-China committee representing special interest groups, from real estate and agriculture to teaching and medicine, as well as lawmakers.

But critics have said she will only further polarise a society riven by mass protests three years ago against Beijing's interference in the affairs of the semi-autonomous city and still divided between those loyal to China and those concerned about its growing influence.

Before landing the top job, Lam served as deputy to her unpopular predecessor Leung Chun Ying, criticised as a puppet of Beijing.

Appointed by Leung as chief secretary in 2012, Lam promoted a Beijing-backed political reform package rejected as "fake democracy" by opponents.

Bespectacled Lam - whose Cantonese name is Lam Cheng Yuet-ngor - is nicknamed "lai-ma" or "wet-nurse" by opponents, in a jibe over what they say was fawning loyalty towards her former boss.

Still, Lam, a mother of two adult sons, is known as a tough and effective enforcer.

In 2007, she personally faced off with protesters over the demolition of a historic pier built during Hong Kong's colonial days under British rule. The landmark was ultimately destroyed.

At the height of the mass street protests in 2014 - known as the "Umbrella Movement" - she met student representatives in a televised meeting about the political reform dispute.

Ultimately, activists failed to win concessions on democratic reform, including fully free leadership elections.

Her attempt to push through a planned Palace Museum in Hong Kong, showing artefacts from the museum in Beijing's Forbidden City, was criticised for being presented as a done deal without public consultation, highlighting what some describe as her "autocratic" style, according to a source who knows her.

She is not well regarded by the opposition democratic camp, with most of the 300 or so democrats seen having voted for former Financial Secretary John Tsang.

Lam was an activist herself during university days in the 1970s, with one photo published in the South China Morning Post showing her marching in protest against the expulsion of four "leftist" students.

She was a student of sociology at the University of Hong Kong and is a devout Catholic.

She came from humble origins, growing up in the crowded district of Wanchai. The daughter of a Shanghainese immigrant who worked on ships and a mother who had never received a formal education, Lam grew up in a cramped apartment shared by four siblings and several families.

But recent gaffes have fanned criticism that Lam - who is usually elegantly dressed and sports a short coiffed hairstyle - is out of touch with ordinary people.

She appeared unfamiliar with how to use the city's ubiquitous "Octopus" travel card to get into the subway platform.

She was also mocked for a lack of common sense after an anecdote related to reporters - about a late-night hunt for toilet paper - revealed she didn't know where to buy essentials in a city packed with convenience stores.

In an interview last month with Chinese state news agency Xinhua, Lam said the government must imbue the young generation with a sense of Chinese national identity.

The government will "strictly enforce the law" against any acts advocating Hong Kong independence, she told Xinhua.