A group trying to stop a big wind farm proposal for King Island has been ordered to pay $35,000 before it can continue with its legal challenge.

No Tas Wind Farms is arguing Hydro Tasmania does not have community support to build the $2 billion project on the Bass Strait island.

It has taken the case to court, using Australian Consumer Laws to fight against it.

The Federal Court heard the group has about $20,000 and would be unlikely to be able to pay costs if its action was unsuccessful.

Hydro Tasmanian sought to force the group put up $165,000 in security.

But Justice Duncan Kerr ruled costs of $7,000 per day for the estimated five-day trial was a modest, but reasonable amount.

The group has seven days to pay $20,000 and the remaining $15,000 before a trail date will be set.