Is there a possibility of drupal showing wrong no. of visitors currently on website? I am facing some problem with the number of users on site.
It's possible, don't know what you use to show the number of visitors, but it depends on how long time it uses to "think" a user is still on the site..
look on your host at the the traffic tools some are better then others, google analytics is usually pretty accurate
yeah its possible.. especially if you have currently have spiders crawling your site.. I'm pretty sure they count those as visitors.
Use a web statistics tracking system, like Piwik or Open Web Analytics & dedicated modules to integrate in drupal, filter out robots trafic