In addition, 33 percent of Australian and a quarter of New Zealand’s social networking users had joined in the past three months.

Melanie Ingrey, Nielsen Online’s market research director in the Asia-Pacific region, said she expects a further significant increase in the near future due to the viral nature of social networking adoption. "As many as one-half of current non-users have already indicated they will sign up within the next 12 months,” she said.

The study also pointed out that almost half of the users, 45 percent in Australia and 48 percent in New Zealand, spent one to four hours on social networking sites every day.

The most popular sites differ in the two countries. In Australia, MySpace was the most popular, followed by Facebook. In New Zealand, Old Friends was ranked on the top and Bebo was second, eMarketer reported.