Nov 11 (Reuters) - Australia's Woodside Petroleum Ltd on Wednesday reaffirmed that its Scarborough and Pluto Train 2 liquified natural gas project is on track for a final investment decision in the second half of 2021, aiming for a first cargo in 2026.

The country's top independent gas producer in March had deferred a final investment decision on Scarborough, co-owned by BHP Group, until 2021 to help rein in capital spending to weather crashing oil prices.

Woodside did not give an updated estimate on development costs for the project, which it has previously flagged at $11.4 billion.

"We estimate the targeted 20% increase in Scarborough's upstream capacity can be achieved at a very modest capex, with virtually no cost impact on the downstream," Chief Executive Peter Coleman said in a statement.

Woodside said it forecasts an internal rate of return of more than 12% for the project off Western Australia.

The company is looking to help fund its projects by selling down stakes in Pluto Train 2 and its Sangomar oil project in Senegal. It is now also considering selling stakes in its infrastructure assets, with strong interest from infrastructure investors, the company said on Wednesday.

Responding to FAR Ltd's plans to sell its stake in the Sangomar to a unit of India's ONGC Videsh Ltd for $45 million, a Woodside spokeswoman said the company is considering whether to match ONGC's bid.

Woodside also narrowed its full-year output guidance to 99 to 101 million barrels of oil equivalent (mmboe) from previous range of 97 to 103 mmboe.

Woodside, which is looking to reduce its direct carbon emission to be net zero by 2050, said it is now aiming for reductions of 15% by 2025 and 30% by 2030 in its net equity Scope 1 and 2 emissions compared with the 2016-2020 period. (Reporting by Shruti Sonal in Bengaluru; Editing by Lincoln Feast.)