Health authorities in NSW have confirmed 12 new coronavirus cases, as clusters associated with a Sydney CBD gym and a pair of schools in the city’s west grow to 52 and 12 respectively.

Nine of the cases are locally acquired, including two members of a south-west Sydney family and a case in Parkes with no known source.

NSW Health said five were linked to known cases or clusters, including three close contacts of previously reported cases to the Sydney CBD cluster, which now stands at 52.

Another was linked to a south-east Sydney case, whose source is under investigation and the remaining three of the cases are returned overseas travellers in hotel quarantine.

Among today’s cases was a contact of a previously reported case of a student at St Pauls Catholic Greystanes and another case in Girraween Public School, bringing the total cluster to the schools to 12.

The new cases come after the state’s Rail, Tram and Bus Union called for the appointment of marshals on public transport to enforce COVID-safe regulations.

After the emergence of coronavirus cases on Sydney buses, the union is calling on the government to hire COVID marshals to enforce physical distancing regulations on trains, buses and trams and ensure all commuters wear masks.

“The state government has introduced a raft of measures for public transport without the means to enforce them,” RTBU NSW Secretary Alex Claassens said in a statement.

Tweet from @NSWHealth

The NSW government has strongly advised commuters to wear masks but Premier Gladys Berejiklian has resisted pressure to mandate the measure.

NSW Health also updated its advisories and said a case reported yesterday that they attended a church service in Prestons, in south-east Sydney on August 30, between 12:30pm – 2:30pm.

Health authorities said anyone who attended this service is considered a close contact and must be tested and self-isolate for 14 days, even if their test result was negative.

Several Sydney businesses were also added to NSW health alerts, with anyone attending these sites considered a close contact who should monitor for any flu-like symptoms.

• Westfield Chatswood Thursday, August 27, 1-1.50pm
• Gram Cafe and Pancakes, Chatswood Station, Thursday, August 27, 11.10am-12.15pm
• Balmain Community Pharmacy, 273 Darling Street, Balmain, Monday, August 31, 11-11.20am
• God’s Power Ministries Heckenberg, 18/7-9 Progress Circuit, Prestons, Sunday, August 30, 2.50-3.30pm
• Quality Suites Camperdown in the foyer, 108 Parramatta Road Camperdown, Saturday, August 29, 3.15-4.30pm
• Leaf Cafe & Co, Lidcombe Shopping Centre, Monday, August 31, 11.30am-1.30pm

There were 29,607 COVID-19 tests conducted during the 24 hours to 8pm Wednesday, up from 20,083 the day before.

-with agencies