Real estate agents are being told they must do better on social media.

The Real Estate Institute of New Zealand's chief executive, Bindi Norwell, said agents had been asking for guidance with social media for some time.

"With more and more people turning to social media platforms when looking to purchase property, it's imperative that our members are seen as experts in this space."

The institute is now offering discounted coaching for its 15,000-odd members through social media training firm Start Social.

About half of the institute's members had used unpaid social media to market a property, and almost 40 per cent had used paid social media.

Wellington agents were most likely to use social media.

But Wendy Thompson, chief executive at Start Social, said when it was done properly, social media offered a cheap and effective way to build a strong brand and reach buyers and sellers.

"The other easy win is to use social media tools at the pointy end of sales; for example, on social media you can target families that are about to have kids come of school age with properties in the school zones, or older people with children leaving home if you have the perfect downsizing apartment you want to suggest to them."

But she said only 2 per cent of posts were seen organically, so agents needed to understand how paid advertising worked. Done "half-well", it could be fatal to a business, she said.

"It is a specialist proficiency that requires knowledge of the rules, language and skills," she said.

"Best of all, results are measurable, and if something is not working, tactics can be adjusted mid-way through marketing a property.

"There are 500 million people watching videos on Facebook every day, thanks to high organic reach. There are over 3.2 million Kiwis on social media every day, an enormous market for real estate agents to be leveraging."