Origin Energy has dropped its resistance to a capital raising, moving to sell $2.5 billion in new equity in response to markets increasingly panicky about resource sector debt levels while key commodities face a prolonged price slump.

The fully underwritten entitlement issue is part of a $4.7 billion package of measures by the energy supplier intended to shore up its balance sheet and avoid its credit rating falling to junk status. The package includes up to $800 million in asset sales, $1 billion in spending cuts and a 40 per cent cut in dividends over the next two years.