Brazil's state-owned oil giant Petrobras, mired in fallout from a huge graft scandal, on Friday posted Q1 revenue down 1.1 percent on the same period last year.

The company reported net income of 5.330 billion reais ($1.778 billion) on sales of 74.4 billion reais.

Last year's Q1 results had brought net income of 5.393 billion reais, the dollar value translating at the time to $2.420 billion -- but the real has shed around a fifth of its value this year against the US currency unit.

Last year's result was a 30 percent fall on 2013.

Petrobras took a writedown of some $17 billion in reporting delayed Q4 results last month, after the kickbacks scandal, which has embroiled dozens of politicians.

Prosecutors estimate that some $2.1 billion in bribes was moved as part of the scheme.

The writedown also took into account cost overruns and the impact of the slump in crude prices in recent months.

Petrobras' market capitalization value has slumped by tens of millions of dollars since the kickbacks scandal broke 14 months ago.

Share value has decreased by more than half as the company battles a mountain of debt and struggles to meet production goals.

"In the first quarter of 2015, a 20.8 percent depreciation of the real over the dollar affected the company result, worth and indicators," Petrobras said in a statement.

The company said earnings before interest, taxes, depreciation and amortization rose an annualized 50 percent to 21.52 billion reais.

It lifted production 11 percent over the period to 2.8 million barrels of crude and natural gas a day, compared to 2.5 million in the previous year.

Last year's final quarter results, audited externally by PricewaterhouseCoopers, gave an annual loss, the first since 1991, of 21.6 billion reais ($7.2 billion).  

Those results calculated the losses incurred from the kickbacks, which spanned from 2004 to 2012.

Petrobras said in January it considered it "impossible" to calculate "correctly, completely and definitively" the damages resulting from the scandal.

Brazilian investigators say they are confident they will recuperate some $360 million in cash siphoned off during the scandal, the worst in Brazil's history.

Before Friday's results, Petrobras ordinary shares closed up 2.3 percent on the Sao Paulo stock market, adding 1.04 percent.