$\ = "\n";
foreach (eval "keys \%{ \$new_hash->$key }" ){ print }

##</code><code>##

my @path = qw(key1 key2 key3);

my $reference = $new_hash;

$reference = $reference->{$_} foreach @path;

$\ = "\n";
foreach (keys %$reference){
    print;
}