The authorities on Friday said builders put up the wrong pre-fabricated wall while constructing subsidised flats in Yuen Long and have since been told to fix the mistake.

Photos posted on social media recently showed the incorrect wall at Long Tin Court.

The Housing Department said the construction firm had mixed up two walls of the same size that have different window designs.

"The structure of the building is unaffected because the pre-fabricated wall involved is a non-structural component," it said in a statement.

It said the Housing Authority's construction team will closely monitor the performance of the contractor to ensure the safety and quality of the estate, which is due to be completed in early 2026.

The department stressed that the authorities have a good system for managing construction contracts, as well as stringent inspection procedures to ensure the quality of buildings.