The Holiday Inn quarantine hotel at Melbourne Airport will close until further notice as an investigation into three coronavirus cases gets underway.

The government agency responsible for Victoria's hotel quarantine system, COVID-19 Quarantine Victoria, says it is a highly precautionary measure.

There are three cases linked to the hotel, consisting of two workers and a woman who tested positive after completing her 14 days of quarantine at the hotel. All staff and residents at the hotel during the exposure period will be considered primary close contacts and will need to quarantine.