Music: Count Us In is an annual event bringing together more than 500,000 students from a range of year levels to sing the same song, at the same time, on the same day.

The young voices will reach a crescendo at 11.30am on Thursday as the lyrics of Come Play Your Part stream out of the classrooms of Mackellar and StPaul's Catholic primary schools.

St Pauls music co-ordinator Veronica Gauci says her students are excited about the event.

"Thirty students from grade 2 to 6 will be participating and we have been practicing every Tuesday from 11am-noon in preparation for it."

Mackellar arts co-ordinator Ginger Martin said the event highlighted the importance of music education.

"The song's message is everybody plays their part and our students all understand how they fit together.

"It's really quite exciting, the senior band are helping the little ones in preparation for the event and even the lyrics are quite uplifting."

She says the LOTE [Languages Other Than English] class will also perform the song in Italian as a display of the universality of music.

"It does really bring the school together, it's a lovely feeling."

Organiser Tina Broad agrees. "It's great to think that wherever you are on the day at that time, you could open your windows and hear the sound of half a million young Australians all focused on the same thing: making music together. There's no better way to remind the community about the value of music."

The event is organised by the Music Council of Australia with support from the federal government, which also enables the delivery of music professional development to primary classroom teachers.

More than 1200 primary teachers will receive training as part of this year's program.