@ar1 = split(';', $num1);
@ar2 = split(';', $num2);

##</code><code>##

# given: @num = ("1;2;3", "4;5;6");
$array[0] = [1, 2, 3];
$array[1] = [4, 5, 6];

##</code><code>##

@array = map { [ split(';', $_) ] } (@num);