(Adds guidance, background) Feb 25 (Reuters) - Yancoal...

(Adds guidance, background)

Feb 25 (Reuters) - Yancoal Australia Ltd (YAL) reported on Monday an over four-fold increase in annual underlying net profit, boosted by robust prices for its thermal and metallurgical coal, and flagged higher expenditure this year as it aims to improve efficiency.

Net profit before one-off items rose to A$868 million ($621.75 million) for the year ended December, from A$211 million in the previous year, the company said in a statement.

Revenue for the period rose 86 percent to A$4.85 billion. The jump in revenue was underpinned by higher overall realised average price for Yancoal's coal products, which rose near 16 percent to A$132.

“In the year ahead we will invest in new fleets and operational efficiencies across our open cut mines, and progress our pipeline of Australian brownfield projects, with a specific focus on the Mount Thorley Warkworth and Moolarben operations," Chief Executive Officer Reinhold Schmidt said.

Yancoal expects capital expenditure in 2019 to be around A$285 million. It spent A$210 million in 2018.

The company said it expects to churn out 35 million tonnes of saleable coal in 2019, a figure it had given last month.

Yancoal's results come at a time when Australian coal imports are facing longer waiting times to clear customs than other supplies at Chinese ports, and the northern port of Dalian was halting Australian coal shipments.

However, China's foreign ministry said on Friday that Australian coal imports to the country continue as normal, although it added customs authorities had stepped up environment and safety checks on foreign cargoes.

($1 = 1.3961 Australian dollars)