I know i'm entitled to time 'n' a half but Am I entitled to a day-in-leau if I work on a public holiday?

At my work I've been told that "if you work the last 5 consecutive weeks (what ever day the public holiday falls on eg. weds), only then am I entitled to a day-in-leau". I beleive this is not tru but I would like to know from you.