use strict;
use warnings;
use XML::Writer;

my $writer = new XML::Writer();

$writer->xmlDecl();
$writer->startTag("Main");
$writer->startTag("NewHits");
$writer->dataElement( "GI" , "Element string");
$writer->endTag("NewHits");

$writer->endTag("Main");
$writer->end();

##</code><code>##

<?xml version="1.0"?>
<Main><NewHits><GI><GI>Element string</GI></GI></NewHits></Main>