Australian schoolgirl Jessica Watson is set to complete her round-the-world solo sail by early next month and become the youngest person ever to complete the epic journey, her spokesman said yesterday.

After more than six months at sea, during which the 16-year-old has endured a brutal storm in the Atlantic and 10-metre-high (33 foot) waves, Watson is now back in Australian waters and heading east for Sydney.

"At the moment it's all going well," spokesman Andrew Fraser told AFP, adding that Watson was covering about 110 nautical miles per day.

"If she stays on that pace she'll be back within two weeks."

Watson departed Sydney on October 18 amid a storm of criticism that she was too young and inexperienced to attempt the 23,000 nautical mile non-stop sail in her bright pink 10-metre (33-foot) yacht "Pink Lady".

But with her friendly rival Abby Sunderland from the United States forced to abandon her own world circumnavigation attempt, Watson is now on course to become the youngest person to sail solo, non-stop and unassisted around the world.

On her most recent blog post, Watson said she had battled the biggest waves of her journey in fierce seas off southern Australia in which her boat had been tipped horizontal to the water.

"These swells were 10-metre liquid mountains, rolling past with tumbling white tops," she wrote last weekend.

"The rest of the week isn't going to be any easier with another front and low pressure system expected, but unlike a few days ago, I'm not dreading it anymore."

Fraser said Watson was on course to sail back into Sydney Harbour on May 8 or 9 - just ahead of her birthday on May 18.

He said there was "zero chance" Watson would become complacent, despite being so close to reaching her goal.

"Every minute of every day, she's on watch," he said.

Britain's Mike Perham became the youngest person, at 17, to sail round the world but rudder problems and other hitches forced him to pull into port three times. Australian Jesse Martin completed the journey aged 18 in 1999.