The investigation comes a day after the Swiss bank was fined $1.5bn (£940m) by regulators in the US, UK and Switzerland for manipulating the interbank lending rate.
The Hong Kong Monetary Authority (HKMA) said it has received information from "overseas regulatory authorities about possible misconduct by UBS involving submissions for the Hong Kong Interbank Offered Rate and other reference rates in this region".
The regulator said that it had launched an investigation to see if any of UBS's actions had a "material impact."
It is part of a worldwide investigation into the rigging of the Libor rate.
The US Justice Department said also charged Tom Hayes, a British former Tokyo-based trader, and Roger Darin, a Switzerland-based managing director responsible for the bank’s Libor submissions, with conspiracy.
They are the first to face criminal charges in the investigation into Libor manipulation by global regulators. Hayes was one of the three men arrested last week in connection with the Serious Fraud Office’s investigation into rate-fixing.
UBS was the second bank to be been fined over Libor after Barclays was ordered to pay hefty fines to UK and US authorities earlier this year.
The UK's Financial Services Authority (FSA) has alleged that the bank's Tokyo office made corrupt payments to brokerages.
UBS's fine is more than three times the £290m fine levied on Barclays in June for attempting to rig the Libor benchmark rate used to price financial contracts around the world.
UBS chief executive Sergio Ermotti said yesterday, “During the course of these investigations, we discovered behaviour of certain employees that is unacceptable. Their misconduct does not reflect the values of UBS nor the high ethical standards to which we hold every employee."
"We have co-operated fully with the authorities and taken decisive and appropriate actions to correct the issues and to strengthen our control processes and procedures.
"We deeply regret this inappropriate and unethical behaviour. No amount of profit is more important than the reputation of this firm, and we are committed to doing business with integrity.”
The FSA said at least 45 people were involved in or were aware of the rigging and that the breaches occurred over a five-year period between January 2005 and December 2010.