Malaysian state energy firm Petronas Wednesday reported that first-quarter net profit in 2013 fell 4.7 percent due to lower oil production but remains optimistic in outlook.

Net profit for the three months ending March 31 was 17.56 billion ringgit ($5.7 billion) compared with 18.43 billion a year earlier, Petronas said in a statement.

The firm produced 743,000 barrels of crude oil in the first quarter, falling from 773,000 barrels during the same three months last year. Natural gas output was 1.41 million barrels of oil equivalent per day, up from 1.34 million barrels.

Revenue rose 1.9 percent in the period to 76.68 billion ringgit from 75.25 billion, backed by higher trading volume for both crude oil and gas amid a strong US dollar against the Malaysian currency.

The company is Malaysia's only representative in the Fortune 500.

Petronas said overall financial performance this year was expected to be "satisfactory" despite volatility in oil prices and global oil demand.

Meanwhile, Tan Sri Shamsul Azhar Abbas, president and group chief executive of Petronas, told reporters that output from its South Sudan operation would pick up next year.

Its South Sudan operations resumed production in March after 15 months of disruption.

"For this year, oil price will average about $95-$100 per barrel and as far as profit is concerned, it will probably be flat," Shamsul was quoted as saying by Dow Jones Newswires.

Last year, Petronas lost around 120,000 barrels of oil a day from South Sudan due to a dispute between the country and its neighbour Sudan over transit fees.