Men arrested in pre-dawn raids released

Two men arrested by counter-terrorism officers in pre-dawn raids have been released as investigations into the killing of NSW police employee Curtis Cheng continue.

A 22-year-old from Merrylands and a Marsfield man, also 22, were picked up along with two teenagers, aged 16 and 18, from Wentworthville, when more than 200 officers searched properties in Sydney's western suburbs.

They were interviewed about the shooting murder of Mr Cheng by 15-year-old Farhad Khalil Mohammad Jabar outside the Parramatta police headquarters on Friday.

The two 22-year-old men have since been released, a police spokeswoman said on Wednesday afternoon.

"A significant investigation remains ongoing ... in relation to those with alleged involvement in the fatal shooting of Curtis Cheng," she said.