* Annual core profit slumps 46 pct, as expected
* Trims underlying EBITDA forecast for FY2017
* Expects to cut net debt to below $9 bln by June 2017
* Shares fall as much as 3.8 pct (Adds analyst comment, share price reaction)
By Sonali Paul
MELBOURNE, Aug 18 (Reuters) - Australia's Origin Energy suspended its final dividend as it scrambles to cut debt and trimmed its guidance, after weak oil prices and spending on the A$26 billion ($20 billion) Australia Pacific LNG project nearly halved its underlying annual profit.
Australia's top power and gas retailer, whose Australia Pacific liquefied natural gas project started exporting this year just as oil and LNG prices slumped, said on Thursday it expects to cut net debt to below A$9 billion by next June.
Underlying profit fell to A$365 million ($280 million) for the year to June 2016 from A$682 million a year earlier, in line with analysts' forecasts around A$370 million.
"While the Board will review each dividend decision in light of the prevailing circumstances, the Board's view is that suspension of the dividend is in the best overall interest of shareholders," Chairman Gordon Cairns said in a statement.
The second unit of two units at the 9 million tonnes a year APLNG project is on track to start producing in the December quarter, Origin said.
The ramp up has been a bit slower than expected while the oil price slump has persisted, delaying the benefits of the massive project, one of three LNG plants that have started up side by side in Queensland since early 2015.
Origin has previously said 2015 and 2016 would be transitional years for the company, but has now pushed that out to include 2017.
"In FY2018 and beyond, as APLNG completes the transition from development to production of its LNG project, Origin expects to see significant growth in earnings and returns, strong cash flow and continuing reduction in debt," Origin Chief Executive Grant King said in a statement.
With both APLNG units operating, the company said it expects underlying earnings before interest, tax, depreciation and amortisation to rise by at least 45 percent to between A$2.37 billion and A$2.6 billion in the year to June 2017, roughly matching market forecasts.
But excluding LNG, the 2017 guidance worked out to $1.8 billion to $1.95 billion, which was lower than the company flagged in February.
"We anticipate a negative reaction to the guidance downgrade," Royal Bank of Canada analyst Ben Wilson said in a note, who added that the suspension of the dividend was expected.
Origin shares fell as much as 3.8 percent in a broader market .AXJO down 0.4 percent.
($1 = 1.3057 Australian dollars)