MPs want mortgage lenders to stop using discredited scientific evidence that is reducing the value of properties where Japanese knotweed has been found.
An investigation by the House of Commons Science and Technology Committee has concluded that lenders are "overly cautious" when offering mortgages on a property where the invasive plant has been discovered.
As a result, some sellers cannot find a buyer who can secure a mortgage, a situation that is not repeated on continental Europe where lenders are less risk-averse, according to the committee.
Call for better evidence
Its report has criticised the seven-metre proximity rule proposed by the Royal Institution of Chartered Surveyors in 2012, which it says has no evidence base to support its use. Instead more recent research suggests the weed doesn't grow beyond four metres.
Norman Lamb, chair of the committee, said: "It is clear that the UK's current approach to Japanese knotweed is more cautious than it needs to be, especially when comparing it to that of other countries.
"We need an evidence-based and nuanced approach to the issue, one that reassures owners and buyers that they will not be subject to disproportionate caution when trying to sell or buy a property."
No greater threat
The report wants more academic research on the spread and effect of Japanese knotweed, a plant that was introduced to the UK in the middle of the 19th century.
Before lending on a property where Japanese knotweed has been found, many lenders demand that a treatment programme is in place to control its growth.
However, the Commons committee noted that the latest research indicates that damage to property from the plant is "no greater than that of other disruptive plants and trees". Its report said the presence of other plants and trees do not have the same "substantial chilling effect on the sale of a property".