Problem: Sometimes the Joomla developer face a problem on their server.The problem is like that:
DirectoryIndex index.php index.htm
The key is to have index.php early and allows the server to accept the index.php file as the start page.
If this does not work, ie: Your host will not allow it, create a blank index.htm page, and put the following code it.
<html> <head> <title>Redirecting.....</title> <meta Http-Equiv="Refresh" content="0;url=http://www.yoursite.co.nz/index.php"> </head> <body> </body> </html>
If necessary, you could do a similar one in the admin folder too, but add administrator/ before the index.php