Some will have taken part in a "Spirit of Anzac" speech competition. The intermediate school section winner, Noah Smith of Tamatea Intermediate, will be the guest speaker at the the commemoration.
The numbers at the service will necessitate the closing of the clock tower entrances to Avondale and Neave Rds, but traffic on major thoroughfare Gloucester St is not expected to be interrupted.
Mr Grant said the RSA was encouraging involvement in organising and taking part in Anzac Day events to help ensure the annual tributes to those who served the country survive and flourish, as the number of veterans become fewer and fewer.
The last survivor of the 100,000 New Zealanders who fought in World War I was Hawke's Bay man Bright Williams, who died in 2003.
The youngest of about 140,000 New Zealanders who served in WWII are now aged over 90.
While returned services personnel include those from more recent campaigns, including the Afghanistan Reconstruction Project, it's estimated that two-thirds of RSA club members are not veterans.
Meanwhile, Havelock North schools won't be going a second round with the multi-school celebration they held on the eve of Anzac Day last year, when about 2500 students from eight schools in the area took part in a centenary commemoration.
Havelock North High School principal Greg Fenton said that despite Anzac Day falling within the school holidays, the school would be represented at the traditional Havelock North wreath-laying service by its Head Boy and Head Girl. The school will hold its own service on the first Thursday of the second term.