* Project "deeply uneconomic investment proposition" minus aid-CEO
* Sydney Airport has until May 8 to exercise 1st right of refusal
* Australia govt says has "ample capacity" to fund airport if needed (Recasts with CEO comments)
By Jamie Freed
SYDNEY, Feb 16 (Reuters) - Building a new A$5 billion ($3.86 billion) airport in Sydney is not economically feasible without government aid, the operator of the existing airport in the Australian city said on Thursday, raising doubts about its likely participation in the project.
"On the present terms, it is a deeply uneconomic investment proposition," Kerrie Mather, chief executive of Sydney Airport Holdings Ltd, said at an earnings briefing, referring to the airport proposed to be built in the western outskirts of Australia's largest city.
"It would be decades before you see reasonable cashflows on a very significant outlay. Perhaps it does make sense for the government to be playing a role in that," Mather said.
Sydney Airport has first right of refusal to build the airport, which the Australian government hopes will boost inbound air passenger numbers to Sydney by about a quarter, or 10 million people per year, from current levels within five to 10 years of opening.
It has until May 8 to take up its development rights. If Sydney Airport declines, the government can build the airport itself or offer the development to other groups, such as pension funds and infrastructure funds.
But that would mean losing its monopoly status in Australia's most populous city when the new airport opens in a decade. Being a monopoly has helped it charge the highest landing fees in Australia and generate large sums of cash, endearing it to investors.
Sydney Airport had initially discussed forms of subsidies with the government, such as funding of earthworks or concessional loans, but no assistance was offered when the government approved the project in December.
RBC Capital Markets analysts on Jan. 31 said the government would need to offer at least A$1 billion of funding to make the project attractive enough for Sydney Airport to develop it. The airline operator's largest shareholder, UniSuper, has said the chances of the development being financially viable for Sydney Airport based on the current terms appears "negligible".
Mather on Thursday did not rule out taking on a partner to offset some of the costs, in a move that would reduce the size of the financial risk but would not boost returns.
However, several infrastructure fund managers and investment bankers told Reuters they are not aware of any partnership proposals even though a decision is due in less than three months. They could not be named because they were not authorised to speak publicly about the matter.
A spokeswoman for the Minister for Urban Infrastructure, Paul Fletcher, said the government had "ample capacity" to fund the new airport if needed.
Sydney Airport reported on Thursday a 10.3 percent rise in 2016 earnings before interest, tax, depreciation and amortisation to A$1.11 billion, in line with market expectations, after international traffic growth rose at the highest rate in 12 years.
Shares of Sydney Airport closed 2.1 percent lower on Thursday, while the broader market ended flat. ($1 = 1.2965 Australian dollars) (Reporting by Jamie Freed; Editing by Dominic Evans and Muralikumar Anantharaman)