Free-to-play games supported by micro-transactions on Xbox 360 are "inevitable", according to one developer.

Hi-Rez Studios boss Todd Harris, who is making free-to-play game Tribes: Ascend for PC and Xbox 360, told Eurogamer Microsoft plans to relax its rules regarding Xbox Live because of industry trends.

Last month a Develop report revealed Microsoft was talking with developers to discuss free-to-play game deals.

The idea is that games can either be monetised by in-game items or premium upgrade costs. Xbox 360 will incorporate a micro-transactions service using Microsoft Points, the report claimed.

As of now, the Xbox 360 version of Tribes: Ascend is on the back burner until Microsoft sorts its free-to-play Xbox Live policy out.

Discussions revolve around how free-to-play games will be updated through Xbox Live and how gamers will be able to play without spending any money.

"It's really just the degree to which the free-to-play model and, even more specifically, constant updates are at - kind of what level of support there is for Xbox, or even PlayStation at this point," Harris explained.

"So the ability to patch frequently, the ability to have it be free-to-play so users can get a taste without any fee. At least from our conversations, both Sony and Microsoft are moving there strategically but there are still some things to be worked out on both the business side and the technical side and the certification side regarding frequency of patches.

"And those issues just need further advancement before we would be comfortable putting a release timeframe on a console version. It's not the case of 'never', but we know all those things we can handle on the PC, so that's why PC is first."

Xbox Live has so far been a closed system, preventing massively multiplayer games, for example, from finding a home on the service.

Final Fantasy XIV Online creator and director Hiromichi Tanaka told Eurogamer last year that a "closed" Xbox Live blocked the game from appearing on Xbox 360.

And PlayStation 3 exclusive MMO shooter Dust 514 is in a similar situation. Developer CCP told Eurogamer at E3 last month that it went with Sony because "at least they have policies that allow us to build the game the way we want".

"They're [Microsoft] seeing where the industry is going," Harris continued. "It's inevitable that Microsoft will move towards that because the industry is moving towards that, and once that groundwork has been laid we would be in a better position to consider Tribes: Ascend for Xbox."

Eurogamer put the free-to-play on Xbox 360 story to Xbox senior product manager David Dennis, who told us Microsoft is looking at "a lot of different models for distribution".

"We're always looking at different models and different ways we can work with partners to bring content out," Dennis said.

"If you look, for example, at the stuff Kudo [Tsunoda, Kinect creative director] showed onstage at E3  Kinect Fun Labs  that's an ad-supported model. Those titles are sponsored. There are different ways you can deploy or distribute games using different types of business models and we're always open to talking to partners.

"The strength we have in the business right now and the momentum we have allows us to experiment and try different things like that and see what consumers like and what they don't like," Dennis continued.

"If there are experiences that they like and want to download because it's ad-supported versus what are they willing to pay for it you'll see us continue in the future to look for a lot of different models for distribution like that."