Following a successful server expansion, Valve is taking the opportunity to invite more users to sample the game before it goes on sale to the general public.
"We've just finished our first significant expansion of DOTA 2 server capacity around the world, and that means it's time to kick this thing up a notch," the firm said in a post on the game's official blog.
"Starting this week, we'll be handing out DOTA 2 in increasing volumes."
Interested parties are encouraged to fill out a DOTA 2 survey to help Valve select a diverse range of gamers to test the upcoming RTS title.
In order to encourage multiplayer and community play, successful candidates will receive two additional copies of the unfinished game to give to friends on Steam.
Valve has also released the first part of the official DOTA 2 comic, titled Tales from the Secret Shop. New volumes will be released every day during the next week.
Valve hinted at a 2011 release date for DOTA 2 during an interview with Digital Spy at Gamescom.
The developer has since confirmed that the game will be released in its current form, following a shorter beta testing phase.
Watch a teaser trailer for DOTA 2 below: