Between 500 and 600 people were evacuated from the shopping centre on Tuesday morning.
"This is something we obviously practise for," Supt McCarthy said.
"The evacuation of the people from the centre went quite smoothly."
Police said around 135 people were taken to the local school which was being used as an evacuation centre.
Firefighters said the building was being inspected by structural engineers and urban search and rescue crews.
NSW General Manager of Westfield, Tim Roberts, said the safety of retailers and customers was paramount.
"Today, and the hours ahead, it's about trying to make the place as safe and secure as possible," he said.
"We are genuinely concerned for customers and retailers."
Fire and Rescue NSW Superintendent Tom Cooper said a crew of search and rescue experts included those with experience working in disaster areas such as Christchurch.
"There are a number of cars in the car park, they will be dealt with separately once the area has been made safe," he said.
Mr Cooper said no structural movement had been detected since 9am.
Urban search and rescues crews will remain at Westfield Eastgardens until further notice.
-AAP