Apple says it loses more money than it makes when repairing customer devices such as iPhones and Macbooks.
Prices at unofficial repair shops vary, but are usually significantly cheaper than an official repair.
The BBC found third parties retailers that would replace an iPhone 8 screen for between £50 and £90.
Responding to the US committee, Apple said: “Repairs performed by untrained technicians might not follow proper safety and repair procedures and could result in improper function, product quality issues or safety events.”
Asked whether it took any action to block consumers from seeking an unauthorised repair, the company said: “Apple does not take any actions to block consumers from seeking out or using repair shops that offer a broader range of repairs than those offered by Apple’s authorised technicians.”
Apple told the BBC it had nothing to add to its written answers to the committee.
Apple also answered questions about the Maps app, which is pre-installed on its iPhone and iPad devices.
In 2012, the company was criticised for removing Google Maps as its default navigation app. Many customers said Apple Maps had launched before it was ready.
In its answers to the committee, Apple said it had invested “billions of dollars” in its map software.
It suggested the reason it decided to develop its own Maps app was to give customers more control over their privacy.