PetroChina's petrol station is pictured in Beijing, China, March 21, 2016. [Photo/Agencies]

Among all non-financial A-share companies, the country's biggest oil and gas producer PetroChina Co tops the list with 1.05 trillion yuan ($162.8 billion) liability, reported Securities Daily citing statistics.

It recorded the liability despite bringing down its debt ratio to 43.8 percent from 45.2 percent a year ago after slashing total debts by 3.5 percent last year.

PetroChina obtained regulatory approval in December to issue no more than 40 billion yuan worth of corporate bonds, according to Xinhua.

The thirst for liquidity came as oil companies reported a weaker year due to nosediving oil price. Brent crude, the benchmark for more than half the world's oil, plunged 48 percent last year.

PetroChina reported a 67 percent slump in net profit to 35.5 billion yuan, marking its worst performance since 1999, according to the company's annual report. The other mainland-listed oil magnet Sinopec reported a 32.1 percent decrease in net profit to 32.2 billion yuan.

Cost management has gained increasing attention, with PetroChina planning a 23 percent, or 155.7 billion yuan, cut on capital expenditure, said the newspaper citing comment from the management.

Oil giants are also eyeing enhanced ownership reform to keep lean, said analysts. PetroChina sold remaining natural gas reserves under its Xinjiang, Southwest, Huabei, Dagang, Liaohe and Changqing subsidiaries to local petroleum administrations for 3.51 billion yuan, in a drive to clarify assets relationship and recover cash flow early, it said in a regulatory filing last November.

The company reported a 26.7 percent decrease in cash flow from operating activities to 261.31 billion yuan and a 25.8 percent slump in cash flow from investment activities.

Financial group Nomura expects Brent crude oil price to recover to $40 per barrel this year and gradual demand and supply rebalancing will likely propel prices to an average $60 next year, it said in a note on Monday.