Wind speeds and wave heights over the world's oceans have been steadily increasing for the last quarter of a century, a long-term Australia study showed on Friday.

The study, conducted by researchers at Swinburne University of Technology in Melbourne of Australia, uses 23 years of satellite altimeter data taken from 1985 to 2008 to show that wind speeds over the oceans have been steadily increasing.

According to Professor Ian Young, the lead author on the paper, the study showed the areas which show increased wind speeds in the study also show increased wave heights.

"Extreme wind speeds have increased over most of the globe by approximately 10 percent over the last 20 years, or 0.5 percent every year," he told ABC News on Friday.

"Extreme wave heights have increased by an average of seven percent over the last 20 years."

"Off the southern coast of Australia, the highest one percent of waves has increased in height from approximately five meters to almost six meters."

The researchers said average wind speeds over most of the world 's oceans have also increased, by at least 0.25 percent per year.

Co-author Professor Alexander Babanin said it is unclear yet how, or if, the trend relates to global climate change.

"All we can say is that there is an overall trend, but extrapolating that into the future has to be done with caution," he told ABC News.

Professor Babanin said the data are potentially useful because they can provide independent validation and verification of what happens to the climate.

The study was published on Friday in Science Express online.