In its response to the government consultation on the changes to Stamp Duty Land Tax (SDLT) charges on buy-to-lets and second homes, the CA argued some buyers will end up being legal owners of second properties they have no beneficial interest in.
It gave the example of a homeowning parent buying a property with their child. Even though the child would live there, it would be considered a second home for the parent and the premium would apply.
The CA said the extra 3% SDLT charge should not apply to transactions in which at least one of the owners will live in the property.
However, homemovers intending to switch out their main residence for a new one may also get charged the premium if they do not have enough time to sell their existing property before buying the new one, as they would be considered second home owners under the new rules.
The government has suggested an 18 month time period to allow for the replacement of a main home. If it goes through, home movers who sell within this time would get a refund of the SDLT surcharge.
However, the CA said it would much rather avoid the charge being levied in the first place. It suggested this could be achieved through declarations from buyers that they intend to sell their previous main home.
It argued that while the 18-month time frame will be enough for a majority of transactions to go through, there will inevitably be cases that take longer, which would not be fair.
The government has also proposed landlords buying more than 15 properties will be exempt from SDLT.
The trade body said it suggested a limit of 10 if a criteria had to be set, but said the figures are random and that there is no reasoning or scientific basis behind either of them.
The government is accepting views on the consultation until 1 February.