Governments have a role to play in arresting the spread of fake news, but they should not be the only arbiters of what is false, said former US president Barack Obama last night.

The 44th president of the United States made the remarks at a charity gala at The Ritz-Carlton, Millenia Singapore, when asked about his views on media literacy during a moderated dialogue.

Speaking on social media companies, he said they, too, play an editorial role in selecting what information should be prioritised and what people see.

Therefore, these firms need to take responsibility as media companies to prevent the spread of fake news, instead of insisting they are merely conduits of information akin to utilities companies, he added.

He noted how countries around the world, including Singapore, have tried to deal with the issue of fake news, by exploring if labels can be applied to flag blatant untruths.

Asked about who should decide what is untrue, Mr Obama cited the example of China, where he said the government makes the call. He added that he is uncomfortable with having only the government make such decisions, as it could lead to fewer checks and balances.

"In any country, if the government's the only one that is deciding what is true and what is not, that's dangerous. Because, let's face it, those who are in power tend to want to look good, that's human nature. And so then you reduce checks and balances over time," he said.

He acknowledged that it is a challenge, and suggested that the judiciary and other independent organisations should also play a role in deciding what is true or false. "The key is for us to recognise this is a genuine problem," he added.

He also said that having more media choices now has allowed more voices to be heard. Harking back to his youth, Mr Obama said there used to be fewer TV stations and fewer programmes to watch.

When he was growing up in Indonesia, he quipped, there were news clips of former Indonesian president Suharto cutting ribbons, which he was not interested in, and one cartoon, which he watched.

Mr Obama was the keynote speaker at the Education Benefit Gala organised by Novena Global Lifecare healthcare and aesthetics group.

During the dialogue, he also spoke about government efforts to arrest climate change. The US last month announced that it had started the process of withdrawing from the Paris Agreement.

Mr Obama said the Paris climate accord negotiations were not meant as an exercise that would solve the problem right away.

Rather, the significance was in first partnering China and then bringing other countries into the fold and acknowledging that all countries have a part to play in solving the problem, he added.

He said public opinion would probably be what moves politicians to make changes, but highlighted Singapore as an outlier.

"Singapore is a rare exception in which the Government in a very technocratic way recognises the problem and takes action," he said, adding this could be due to the country's small size.

Mr Obama also spoke about activism among the young when asked about his thoughts on climate activist Greta Thunberg, a 16-year-old from Sweden recently named Time magazine's Person of the Year.

While he praised their passion and idealism, he said young people are often frustrated or burnt out if they do not get 100 per cent of the change they hope for.

His advice for young people pushing for social change is to recognise that there are existing ways of doing things and therefore, people are naturally going to be hesitant about wholesale changes.

"So you have to educate people to make them feel as if they're not taking such huge risks," he said.

After leaving the Oval Office, Mr Obama set up the Obama Foundation with his wife Michelle to cultivate young people into leaders of social change around the world. Mrs Obama is also in Singapore, and yesterday shared details from her personal memoir, Becoming, to an audience at the Singapore Expo.

The one-hour dialogue with Mr Obama, where he displayed his trademark charm, often drawing laughter from the audience, covered other topics including inequality, education and politics.

At the start of the dialogue, he charmed the crowd, saying thank you in Malay when introduced.

Asked about his life after the presidency, he said to laughter: "First of all, I had to make it all up to Michelle by doing whatever she wanted. A spouse of a political leader is challenging and she did an extraordinary job. So the first thing we did, I took her on vacation. We probably also slept for a week."

On work-life balance, he said the toughest time for his family was during the two years when he was campaigning for the 2008 US presidential election.

Talking about how his wife covered for him at home, he said: "She was mad, but she still did a great job."

Last night's dinner raised funds for four Singapore charities that support education and training for marginalised women and children from disadvantaged families.

The charities are: Dreams Academy (South Central Community Family Service Centre), Singapore Council of Women's Organisations Service Fund, Daughters Of Tomorrow and the Singapore Muslim Women's Association.

Among those in the audience of close to 500 were tycoons, philanthropists, Malaysian royalty, tech entrepreneurs, lawyers and teachers.

Before the dinner event, Mr Obama also met Prime Minister Lee Hsien Loong.

Said Mr Lee in a Facebook post: "Happy to see the Obamas having more time to spend together, even here in Singapore. Looking forward to our next meeting!"