MYOB general manager Julian Smith said this follows a similar pattern seen in Australia.
"After a steady take-up of social media, usage from business has fallen off significantly," he said.
"For a business owner who might be preoccupied with the day to day challenges of running a business in a sluggish economic recovery, maintaining an active social media presence is clearly not easy."
While many businesses are interested in social media, finding the time or resources to manage a variety of online marketing tools was tough, Smith said.
Search engine marketing has also fallen from 33 per cent last year to 28 per cent now.
Again, this was probably because business owners found search engine marketing too resource-intensive and time-consuming, Smith said.
"It requires specialist knowledge and expertise that is probably not available to many small businesses.
"We know, however, that the majority of consumers will search online first before choosing a product or service, so this is an area where businesses are missing out if they do not have the time or resources available."
The study found more businesses (45 per cent) were now using the internet to pay suppliers, up 5 per cent compared to August 2011.
Forty-four per cent were buying products or services online, the same as last year.
Smith said "time-poor" business were more likely to be using tools that made it easier to run a business.
"Online tools that require large amounts of time and energy are simply not going to pass that test."
Another area seeing increased use was email marketing and electronic direct mail, with 28 per cent of businesses using electronic direct mail. That is 3 per cent more than last year.
A reason for this could be that business owners were simply more comfortable using familiar methods of communication, Smith said.
"We're seeing more businesses than ever choose to do their marketing via email, be it through regular newsletters or one off product promotions." Younger Business Owners More Social
Not surprisingly, social media uptake generally differed according to the age of business owners, the study showed.
Of Gen Y business owners, 42 per cent were using social media in their business, compared to 21 per cent of Gen X business owners, 20 per cent of Baby Boomers, and 12 per cent of business owners over 60-years old.
The MYOB Business Monitor is conducted by Colmar Brunton.