(Reuters) -- State-owned Royal Bank of Scotland is expected to pay out up to 400 million pounds in bonuses to its corporate banking staff as it gets ready to unveil a full-year loss forecast at up to 1.2 billion pounds on Thursday.

The move is expected to increase anger that the bank is still paying large salaries while thousands, including more than 30,000 layoffs at the bank in the last three years, lose their jobs in a weakening global economy.

RBS, 82 percent owned by the government after it was rescued during the 2008 financial crisis, is also in the firing line over high awards to staff as British taxpayers sit on a 21 billion pounds paper loss on the 45 billion pounds pumped into the bank.

The bank is likely to at least halve the bonus pool for its investment bankers from the 950 million pounds awarded for 2010, people familiar with the matter have said.

Sky News said on Wednesday the bonus pool will be between 390-400 million pounds.

The chairman and chief executive of RBS waived their bonuses this month after politicians from all of Britain's major parties called on them to refuse the awards.

RBS's investment banking income has been hit hard by the euro zone debt crisis and it plans to substantially shrink the business after the government said it should focus more on retail banking. It will cut another 3,500 investment banking jobs.

The cuts will mainly hit its equities and advisory operations -- it sold its historic Hoare Govett stockbroking unit to American bank Jefferies -- as it plans to remain in its areas of strength such as fixed income and foreign exchange.

Chief Executive Stephen Hester has axed 34,000 jobs since arriving three years ago and this month said the political pressures that went with his job had led to some "deeply depressing moments" and made running RBS harder than that of other top jobs at rival British and international banks.

Although RBS may make a fourth-quarter profit at the operating level, the impact of writedowns and restructuring costs is expected to push it into a net attributable loss, down from a third-quarter profit of around 1.2 billion pounds.

Credit Suisse has forecast a fourth-quarter loss of around 1 billion pounds, Nomura has put the loss at 1.8 billion while Bank of America Merrill Lynch reckons the loss could reach 2.4 billion.

Espirito Santo forecast a full-year net loss of around 700 million pounds for RBS while Deutsche Bank put it at around 1.2 billion.

With RBS's turnaround likely to take longer than expected as regulations intensify across the industry, the timetable for the sale of any of Britain's stake back to the private sector has been pushed back. That has prompted talk the government may need to sell some of its stake at a loss at first.

(Reporting by Sudip Kar-Gupta; Editing by Mike Nesbit)