INTERVIEW-Australian Greens set to be kingmaker after poll

* Greens set to control Senate

* Greens and govt set to clash of carbon price

* Mining tax fate rests with Greens

By James Grubel

CANBERRA, July 8 (Reuters) - Australia's Greens party is on course to win control of the upper house Senate at elections that loom within weeks and will seek to push environmental policies to the fore of the next government's agenda.

The Labor government is expected to snare a narrow victory at the election, possibly in late August, but regardless of who wins the poll the next government will probably rely on the Greens to pass laws on everything from the economy to the environment.

And Greens leader Senator Bob Brown has flagged that he will be expecting green policies, in particular a carbon price, in exchange for his party's support.

But the Greens and a future Labor government are set for a tumultuous relationship after Gillard again said she would not consider a carbon price until 2012. "The pricing of carbon, I think, is best done through a market-based mechanism, the Carbon Pollution Reduction Scheme, and the 2012 timeframe stands there," Gillard said on Wednesday.

"Individuals in this country want to do something to reduce their own carbon footprint. I believe the nation wants to reduce its carbon footprint, so we'll be talking about that and speaking about what we can do in the lead up to a decision in 2012."