Today at last I have updated the Nagios package which was delayed from quit sometime.
Updating was quite transparent, only the index.php page has been replaced. Actually instead of displaying the default Nagios index page I have changed it to display the "Host Group Summary" page to all using Nagios web UI.
So all I have to do to change
/usr/share/nagios/index.php (path might be different if installed from source)
frame src="main.php" name="main" frameborder="0"
frame src="/nagios/cgi-bin/status.cgi?hostgroup=all&style=summary" name="main" frameborder="0"