A house in Canberra's north has been sold through a South African real estate scam without the owner's knowledge.

The fraud was reportedly revealed after the South African-based owner contacted the real estate agent to question why rent payments on the investment property at Macgregor had stopped.

The fraudulent sale of the house was made without face-to-face contact and completed using emailed or posted documents.

Real Estate Institute ACT chief executive Ron Bell said agents must be vigilant as the number of fraud attempts was growing.

"Agents need to ask a lot of questions, particularly when it is an overseas buyer or seller," he said.

"When everything is in written communication, via email, and email addresses are changing, you can start to feel something is going on.

"People should verify signatures and verify the material that has been given to them and they can do that through any [Australian] Embassy that is overseas."

Mr Bell said real estate agents had no liability in such situations because they followed instructions to sell.

Ambiguity over who will be the financial loser: expert

In Western Australia there have been two successful property sales and six attempts by fraudsters to exchange properties since 2010.

Three people were arrested in South Africa earlier this month after they attempted to sell a unit at Mandurah, south of Perth, worth $250,000.

"They have been dealing with the South African police, and this lady is going to have to do the same thing," Mr Bell said.

"And it is going to be a very lengthy and expensive process.

"The money has gone to South Africa, so trying to find it and track it down is going to be a nightmare."

According to legal experts, there is ambiguity of over who will be the financial loser in this fraud case, depending on legal and conveyancing checks.

The original owner would be expected to challenge the new buyer in order to return the title ownership to them.

If unsuccessful, they would have to chase the money from the completed sale through legal channels overseas as compensation.

Alternatively, the new owner would need to pursue their money.

All real estate agents in the ACT have been sent a checklist to follow when overseas owners ask via email for a property to be sold.

Attorney-General Simon Corbell said real estates must be vigilant.

"It's critical that they identify that the person seeking to sell the property is the actual and proper owner of the property," he said.

He said it was the first scam of its kind to take place in the ACT.

ACT police have confirmed they are investigating the fraudulent sale.

"Clearly that transfer has been affected due to what would appear to be a fraudulent act and that's now under investigation," Mr Corbell said.