Social media companies such as Facebook face a controversial EU privacy crackdown that would prevent them from reading private messages sent between individuals.
The so-called "ePrivacy" regulations, currently being debated in Brussels, are designed to hand citizens extra privacy protections against internet companies.
However, industry bodies have slammed the proposals as "unreasonable" and potentially "careless", claiming they will impose a huge burden on technology companies of all sizes.
A letter to the European Council signed by 57 technology and internet groups, including techUK, the European Tech Alliance and the Washington-based Information Technology Industry Council, warns of a "considerable negative impact" that will "extend to all sectors of the EU digital economy".
It warns that the proposed regulations are overly strict and will prevent legitimate data processing, even when there is little risk of a person's privacy being breached.
For example, communications between machines would be covered, potentially hampering new technology such as driverless cars.
The rules have been delayed by Brussels disagreements but are due to go into force this year. It comes just weeks after the GDPR data privacy laws, which have proved to be a headache for businesses.
Facebook scans the contents of private messages, including photos and links, to determine if they break its rules. It also monitors the text of messages if they are reported by a user.
Until recently, Google scanned emails in order to target adverts. Other services such as Skype and Apple's iMessage would also be covered by the rules, which aim to force tech companies to abide by the same principles as telecoms operators.
The proposed regulations would require the companies to obtain explicit consent before reading private messages and may also apply to metadata such as who has contacted whom, and at what time.
The European commission, parliament and council must all adopt a formal position before reaching a compromise on new legislation.
The commission and parliament agreed their positions last year and council members debated their proposals at a meeting on Friday.
Facebook's recent Cambridge Analytica controversy is believed to have raised pressure on Brussels to press ahead with the rules. Companies argue that many of the concerns over data processing are already covered by the existing GDPR laws.
"The ePrivacy proposal has departed from the laudable objective of protecting the confidentiality of communications and goes on instead to greatly limit the processing of a broad array of both personal and non-personal data," the letter to the EU Council says.
"The considerable negative impact of an inflexible ePrivacy [law] will extend to all sectors of the EU digital economy - from digital media to connected cars, medical technology and smart manufacturing - which will be exposed to additional burden at best or, at worst, unable to continue offering and innovating their products and services using data."