Former prime minister Helen Clark is more influential on social media than Michelle Obama and Arianna Huffington, according to online magazine Richtopia.

If Michelle Obama wants to up her game on social media, she could do worse than turning to former New Zealand prime minister Helen Clark for a few tips.

Clark, who heads the United Nations Development Programme, has been named the sixth most influential female leader on social media by online business, economics and finance magazine Richtopia.

Her ranking on the Top 100 list puts her ahead of the First Lady of the United States, who came in at eighth, and Huffington Post editor-in-chief Arianna Huffington, who took out the ninth spot.

But Clark wasn't quite influential enough to threaten US presidential hopeful Hillary Clinton, who topped the list ahead of everyone's favourite talk show titan, Oprah Winfrey.

Clark expressed her happiness via Twitter and Facebook on Tuesday, describing the list as "interesting" and saying she was pleased to be sixth.

"Social media is a great vehicle for hearing what people think about issues and events, and for providing a way to communicate directly. Thanks all," she posted on Facebook.

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Richtopia's list is decided by an automatic algorithm, which takes into account various metrics from Twitter, Facebook, Wikipedia, YouTube, LinkedIn and Instagram.

Clark has proven to be a big fan of Twitter since signing up in 2010. She has tweeted more than 27,000 times since then and has amassed 103,000 followers.

By that measure, she blows many of her rivals on Richtopia's list out of the water.

Michelle Obama's tweet count was at 766 on Tuesday, Hillary Clinton was at 2434, and Oprah had almost 11,000 tweets to her name. All three women have many millions of followers hanging off their every keystroke.

Clark is also a much more prolific tweeter than the man who succeeded her as prime minister. As of Tuesday night, John Key had tweeted only 3455 times since signing up in 2008.

Richtopia's list is not the first time Clark's influence has been recognised either. In 2014, she was named the most influential living New Zealand woman in Westpac's Women of New Zealand survey.

Clark received 34 per cent of the vote, well ahead of Olympic gold medallist Valerie Adams on 13 per cent and Dame Alison Holst on 6 per cent.

It has been suggested that Clark may be in line to replace UN secretary-general Ban Ki Moon when his second term expires in 2016.

THE TOP TEN

1. Hillary Clinton

2. Oprah Winfrey

3. Nancy Pelosi

4. Maria Shriver

5. Dilma Rousseff

6. Helen Clark

7. Katie Couric

8. Michelle Obama

9. Arianna Huffington

10. Emma Watson