Jersey's competition regulator is stepping up surveillance of the construction sector, particularly the scaffolding, aggregates and concrete, and home-building markets.
It follows a year-long review, which has concluded the industry needs more effective competition.
The watchdog says high prices, limited competition, and difficulties getting an available builder were among concerns from homeowners.
The Jersey Competition Regulatory Authority says prices are higher here than in other jurisdictions, with labour costs, logistics and transport all major factors.
The report highlights limited choice for homeowners and the unpredictable costs and contractor shortages faced by small businesses
It found that larger firms were more positive about getting competitive quotes and therefore had fewer concerns about the market.
The JCRA warns that 'without strong and effective competition, the sector's resilience and sustainability could be at risk.'
It has announced closer surveillance - in particular of the scaffolding, aggregates and concrete, and home-building markets, looking for potential anti-competitive practices.

CEO Tim Ringsdore said: “Since publishing our draft report in April, we’ve heard loud and clear from businesses and consumers. There are real concerns about how the construction sector operates – and we’re committed to further surveillance of the market.
"This isn’t about pointing fingers – it’s about building a stronger, fairer sector. Jersey needs a thriving construction industry to deliver homes, infrastructure and jobs. Effective competition is key to making that happen.”
Anyone with information about unfair behaviours, such as price-fixing, should report it 'in confidence' to competiton@jcra.je.
The watchdog says it is developing advice to help businesses collaborate fairly without harming competition, and updating its guidelines on anti-competitive arrangements.
It will run awareness sessions for the trade next year, and has already relaxed its rules to encourage business to 'exit any anti-competitive arrangements'.
The JCRA's report follows the closure of several large and established Jersey building firms in the past two year, including AC Mauger, Camerons, JP Mauger, Kalmac, K Land Construction and Nicholson builders, citing rising costs as a major factor.


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