The Duchess of Sussex has encouraged young girls to take inspiration from world leaders like New Zealand's Prime Minister Jacinda Ardern.

She spoke about Ardern as a role model during her speech for the global Girl Up leadership summit.

"We can take inspiration from women like Prime Minister Jacinda Ardern, who brought New Zealand together to swiftly and boldly tackle Covid-19," she said.

She urged girls to challenge "world leaders and executives" in the fight for equality in her first major speech since quitting the royal family.

She said they needed to "push" and "challenge" those "in the halls and corridors and places of power" – and even quoted the Dalai Lama in a call for compassion.

And she said 1-year-old son Archie would be "cheering" them on, along with her husband Prince Harry, as they "continue marching, advocating, and leading the way forward".

Meghan recorded the video message for young women taking part in the global Girl Up leadership summit. Other speakers at the two-day virtual event included Hillary Clinton and Michelle Obama.

The Duchess, 38, said: "I want to share something with you. It's that those in the halls and corridors and places of power-from lawmakers and world leaders to executives – all of those people, they depend on you more than you will ever depend on them. And here's the thing: They know this."

The Duke, 35, and Duchess have been living in the US since March as part of their plan to pursue lucrative commercial careers outside of the royal family.

However, Meghan was not paid for her keynote speech to Girl Up, started by the UN Foundation in 2010 to help support agencies that focus on adolescent girls and inspire them to achieve gender equality and social change.

The Duchess quoted the Dalai Lama as she urged the summit to exercise compassion, particularly online. "Compassion doesn't mean we shouldn't feel anger and outrage when we see blatant injustice all around us... But I challenge you to broaden that feeling.

"The Dalai Lama famously said, 'compassion is the radicalism of our time'. Compassion means seeing the pain and suffering of others and knowing it's our duty to try to help relieve it."

In one of a number of seemingly pointed references to the couple's departure as royals, Meghan urged: "Continue to believe in yourselves, believe in what makes you unique, and don't be afraid to do what you know is right even when it's not popular, even when it's never been done before; even if it scares people. And even if it scares you."

She added: "Often, it's fear that paralyses us and stops us from being brave and being bold. But don't underestimate that you have some of the answers. Don't underestimate your ability to push through the fear.

"You have, rooted in your convictions, the ability to craft a world that you know is just and kind. The hardest part – and it was the hardest part for me – is to chase your convictions with action."

She and Harry have also taken part in a series of video conference calls, tackling issues including the Black Lives Movement, and, more controversially, the history of the Commonwealth.