PetroChina on Thursday said first-half net profit increased 5.6 percent for 2013, citing a boost from policy reforms, which helped narrow losses for its refining and chemical businesses.

China, one of the world's largest oil consumers, brought in fuel pricing mechanisms in March that are more in line with international market standards, giving more room for oil companies to set prices closer to market rates.

PetroChina, the country's largest listed oil company, said in a filing to the Hong Kong Stock Exchange on Thursday it recorded a net profit of 65.52 billion yuan ($10.70 billion) for the first six months ending June 30, compared to 62.02 billion yuan for the first half of 2012.

Revenue rose 5.2 percent to 1.10 trillion yuan, compared with 1.05 trillion yuan in the same period last year.

"The group successfully reduced losses of the refining and chemicals segment," company chairman Zhou Jiping said in the statement.

The refining segment saw a 45 percent drop in operating losses to 15.86 billion yuan, compared with 28.88 billion yuan from the same period last year.

In March, Beijing authorities brought domestic fuel price settinga closer in line with international standards, swaying from an old practise where domestic prices were often fixed lower than market prices, squeezing the profits for refiners.

However, PetroChina said global economic uncertainties, China's slowdown in growth, and oversupply of oil globally are challenges that the company has to face for the rest of the year.

"The recovery of the global economy will remain highly uncertain in the second half of 2013," Zhou said.

"The supply in the international oil market may slightly exceed the demand. The crude oil price is likely to continue to fluctuate at high levels," he said.

"For the second half of the year, it is expected that there maybe some difficulties for the rebound of the domestic economy," he said.

The company's rival CNOOC reported on Tuesday its first-half net profit rising by 7.9 percent year-on-year.

The Beijing-based company reported in March a fall in full-year net profit by 13 percent for 2012, citing a slowdown in the growth rate of the Chinese economy.

The Chinese economy expanded 7.8 percent in 2012, its worst performance in 13 years, due to weakness at home and in key overseas markets.