Why the technology restriction?

There is something of a disjunction between your problem description and the title of your node. What is it that you actually want to achieve? Maybe you should fill us in on some of the bigger picture?

BTW, your sample could be better (for some definition of better) written as:

use strict;
use warnings;

my @array = (["1", "1", "3"], ["1", "5", "6"], ["1", "1", "3"]);
my @unique;
my %seen;

$seen{$_}++ or push @unique, $_ for @array;
print "$_->[0] $_->[1] $_->[2]\n" for @unique;
[download]

although @unique is only required if order is important.

Oh, and your array initialization is completely broken. At the very least you should use the form I've shown above.