Investment bankers in Hong Kong have been warned over the quality of their paperwork in filings for initial public offerings after a boom in listings in the Chinese territory.

Hong Kong financial regulators sent letters to banks in the territory highlighting concerns, including failures to address regulator questions and poor descriptions of the business models of companies seeking to list. The letters also drew attention to text that was copied and pasted from previous prospectuses, according to people familiar with the warning.

The letters, sent in recent days, come as investment banks are beefing up staffing in Hong Kong to handle a revival in listings, which are principally coming from mainland Chinese companies using the territory as a base to raise offshore funds for international expansion.