Another seven cases have been confirmed up until midday today.

The last time NSW active cases increased by more than 10 was in mid-April.

From today’s cases, four are returned travellers currently in hotel quarantine and two of those returned from Victoria but self-isolated and have no close contacts that could present new virus issues.

Eight of the cases identified yesterday include five who attended the pub and three contact of already-confirmed cases.

Dr Chant said some of the identified cases attended the following venues while potentially infectious and anyone who was there during the listed dates have been urged to get tested for COVID-19.

Despite the rapid spike in cases stemming from the Casula pub, Dr Chant said there is not yet a need to lock down the suburb until cases without known contacts are found.

“At this point in time our efforts are focused on getting high rates of testing and whilst the fact that I’m announcing that we’ve had 21 cases linked to the Crossroads Hotel or that cluster, to some extent that represents a success because everyone of those cases we can find, we can stop that ongoing transmission,” she said.

“If we see an emergence of cases that are not linked to either known cases or the Crossroads (Hotel) – attendants on those day – then obviously that will lead us to reflect on additional measures that we need to take in that area.”

The updates come after Sydney casino, The Star, earlier confirmed to the ASX that a patron who attended the venue had tested positive for coronavirus.

“The Star is working closely with NSW Health to respond to this information, including the conduct of contact tracing (which includes staff members),” a statement read.

The Star is operating at a reduced capacity to adhere to coronavirus restrictions.

Meanwhile, a Sydney Catholic school has told parents that a number of their teachers were at the Crossroads Hotel in south-west Sydney earlier this month.

The letter from St Francis Catholic College in Edmondson Park told parents a group of teachers visited the hotel on their personal time on Friday, July 3.

9News reporter Chris O’Keefe said the number of teachers affected was “about 25”.

The school confirmed each affected teacher had taken a coronavirus test, with every result so far being negative.

“We are now only waiting on a final few results to come through,” the letter, signed by principal Simon Abernethy and Wollongong diocese director of schools Peter Hill, said.

The school said it had told the Public Health Unit of the situation, and would undergo an extra deep clean before the start of the third term.

Dr Chant said it was vital that anyone who worked or went to the hotel between July 3 and 10 come forward for testing, whether they had symptoms or not.

Among those going into isolation is federal Labor MP Anne Stanley.

Ms Stanly says she dined at the hotel on Saturday night.

In a tweet, the member for Werriwa said she has been tested for COVID-19 and is starting self-isolation for 14 days.

Last night, Planet Fitness Gym in Casula, which is within hundreds of metres of the pub, closed, with management putting a sign up on its front door to say one of its staff members has tested positive for COVID-19.

The Crossroads Hotel outbreak has triggered a rush for coronavirus testing across Sydney’s south west this morning.

Long lines of traffic are forming near Campbelltown, Liverpool and Fairfield hospitals.

There is also a pop-up clinic at the Crossroads Hotel.