Real estate agents, particularly women, have been urged to take "sensible precautions" after a woman was allegedly sexually attacked in an empty south Auckland house as she waited for a client.

The 51-year-old woman was waiting for a client at a show home in the Karaka Lakes development in Papakura, on the southern outskirts of metropolitan Auckland, about 2pm on Friday when a man allegedly tried to rape her.

She fled to the bathroom, locked the door and called 111.

The Real Estate Institute of New Zealand said such attacks were not common but people needed to take sensible precautions.

Institute chief executive Helen O'Sullivan said any woman would think they were at least moderately safe in broad daylight in the middle a suburb.

"The usual rules for keeping safe apply. You let people know when you are going and when you expect to return.

"I don't think these incidents are any more prevalent amongst the real estate community than women in the community generally.

"It is a risk and it is really unfortunate."

However, it could be a risk to meet people alone, Ms O'Sullivan said.

"You should take sensible precautions but you should also take sensible precautions when walking down a dark alley at night."

The attacker, who had yet to be found after fleeing the house, was a slim Maori, in his late teens or early 20s and of medium height.

He was clean-shaven and had a tribal tattoo on his left bicep.

He wore black leggings, a black t-shirt and motorcycle boots.

Anyone with information is asked to call police.