Consumer Affairs Victoria (CAV) has launched legal action in the Federal Court against two real estate agencies over allegations of underquoting in Melbourne.

CAV alleged the agencies marketed properties knowing the vendors would not sell for a price within the listed range, or that the properties were unlikely to sell for the price listed.

The watchdog accused Fletcher and Parker in Balwyn of offences relating to 25 properties it marketed in 2015, and Hocking Stuart Doncaster of breaches involving nine properties in 2014 and 2015.

Melbourne house prices jumped by 13.7 per cent last year, second only to Sydney.

Complaints relating to underquoting to CAV have risen from 123 in 2013-14 to 339 in 2015-16, leading to the creation of Taskforce Vesta in mid-2015 to investigate the practice.

The taskforce carried out 200 snap inspections of real estate sellers across the state last year, investigating incidents where real estate agents had advertised properties for a price that was less than the vendor's reserve price, or well under the likely sale price.

Then consumer affairs minister Jane Garrett said the taskforce was established to stamp the practice out.

"I've ordered 200 comprehensive inspections to be taken, surprise inspections, for real estate agents right across Victoria," she said.

"From that we have some 340 files opened and a number of active investigations and prosecutions."

The CAV was successful in another case late last year against Hocking Stuart Richmond, which saw the agency fined $330,000 plus $80,000 in legal costs.

In that case, Justice John Middleton said the agency's price ranges created the "illusion of a bargain" and consumers were likely to be "significantly inconvenienced, disappointed and deceived".

"Some may have missed the opportunity to buy elsewhere, being lured into a bargain that did not, and was never going to, eventuate," he said.

"Similarly the vendors of other properties, who were not marketing their properties in the same way, may have missed out on getting potential purchasers into their properties."

In a statement, the agency said it regretted the "mistakes" it had made.