Sci-fi MMO Defiance is going free-to-play.

The switch will happen on June 5 for PC and July 16 on PlayStation 3. Plans for the Xbox 360 version are still pending, said developer Trion Worlds.

Defiance launched last year, and at the time Trion went with the old-school retail model of just selling a boxed product rather than opting for a subscription.

However, the developer told Polygon that going free-to-play was the plan all along, and that those who paid US$50 for the game at launch may expect special treatment.

As such, they will receive a 30-day "Paradise Patron status" which boosts their character stats, a discount in the game's online store, and 1,000 in virtual currency to use there.

A recent patch for the game introduced scaling quests and rewards, so low-level missions will be more worth the time of an experienced player.

In addition, lower level players will be auto-levelled up so they can participate in tough group events.

"We really wanted Defiance to have that feeling of accomplishment and achievement, but we had to first solve how to handle dynamic adjustment,” said the game’s creative director Trick Dempsey.

“Those things needed to be in place, or else people would have a hard time playing together.

"This change provides everyone with lots of other people to play with in a massive co-operative experience."

Trion Worlds CEO Scott Hartsman said the switch would make things simpler for those investigating the game as a result of watching the TV show.

“With a game actively promoted on a TV series, we do want it to be as easy and as fast as, 'I saw this game mentioned on the show, I downloaded the client; oh, cool, now I'm playing it',” said Hartsman.

"Asking people to pay full price in the middle of that is too big of a barrier."

Defiance's second TV season launch on the SyFy channel on June 20.