Two teenagers are among five males arrested in early morning counter-terror raids across western Sydney linked to the fatal shooting of police accountant Curtis Cheng.

More than 200 officers executed a co-ordinated series of raids in Guildford, Wentworthville, Merrylands and Marsfield about 6am.

The group have been taken into custody and will be interviewed at various police stations in relation to Friday's shooting outside police headquarters at Parramatta.

The raids come after a 17-year-old boy who attended the same high school as the teenager who fatally shot Mr Cheng was arrested on his way to school yesterday.