Yes it is possible but not without a plugin.  Although it is good, the moderator permissions are not as customized as they probably should be with the core Install.  I have been considering a plugin for this myself but i fear that there are not enough event hooks in place in the core code to achieve the customized final product.   

Also it will get better, with each release of Oxwall i have noticed that the moderator permission feature is a little more customized.  Although the past changes have been small i do feel that in a near future release there will be more ways to customize moderator permissions.  

dave 

Alain Bertrand, till the Oxwall 1.7.2 version there was a  list of users pending approval on the dashboard page. In 1.7.2 version the moderation panel have been changed and also was implemented a new flag feature. Now you can flag users, which is why we had to separate flagging feature and approve feature.
We know that it is omission from our part, this will be fixed or redesigned in other way in the nearest future. Presently the full list of unapproved users is available only to the admin or moderator who has access to the admin panel as well and by using the direct link: http://yoursitethingie.com/users/waiting-for-approval .

Or we could propose you to use Premoderation plugin: http://www.oxwall.org/store/item/1012 . This plugin allows webmasters to pre-moderate all new content that’s being added to the site, including users, avatars, photos, videos, events, groups, forum posts, etc.

Thanks Taissa i had questions about that as well... thank you for the explanation :)