The result was at least $200 million worse than the market had expected last month.

The announcement was made to the Australian Securities Exchange at 7pm, after trading closed.

It said the company would be unable to continue as a going concern unless it could complete a potential capital raising, restructuring or ``alternative transaction''.

In the meantime, Gunns would require the support of its lenders just to stabilise the company.

Northern Tasmanian financial analyst Tony Gray said the result showed  that the underlying business had lost more money.

``Who would buy them (Gunns) and who would give them money to keep them going now?'' he said. 

The $903.9 million net loss compared with a $355.5 million loss last year.

Impairment charges reduced the value of the company's forestry assets by $749.2 million.

Gunns reduced the carrying value of timber processing assets by $43.8 million.

Unaudited preliminary underlying earnings before interest and tax for the past year was reported at $26.7 million, compared with $41.6 million in 2011.

The statement repeated advice previously given to the ASX that the affect of declining stumpage prices and its asset position had raised uncertainty about financing the proposed $3 billion Bell Bay pulp mill.

Gunns had therefore treated $217 million of development costs as an expense.

Given the state of  woodchip markets and domestic timber demand, it expected its 2012-13 earnings to be ``materially less'' than 2011-12.

 Gunns said its share trading suspension should continue.

However, Mr Gray said that it was time for the ASX to instruct Gunns to return to trading.

``The shame of it is that through all this people have not had the opportunity to either buy into the company or sell out,'' he said.

``The idea of a trading suspension is as a short-term thing.''

Gunns shares last traded in mid-March at 16.