A reputable international trade group says the World Trade Organization will soon rule that Ontario's green energy policies contravene with international guidelines.

The International Centre for Trade and Sustainable Development says a WTO preliminary report has found that Ontario's feed-in-tariff system is discriminatory against foreign suppliers of equipment for renewable energy generating facilities.

The feed-in-tariff system — established in 2009 — requires participating electricity generators in Ontario to source up to 60 per cent of their equipment in the province if they want to be eligible for subsidies.

Japan filed a WTO complaint against the Ontario government two years ago, arguing that the requirement amounted to "illegal subsidies" for Ontario companies.

The European Union, who joined in on the complaint last year, added that the scheme goes against the international WTO provisions.

According to the Geneva-based group, the WTO is expected to make the decision public in November.