MANILA - Tax payments of oil companies surged 56% in the first semester of the year just as the government is set to look into their financial books due to allegations of overpricing and cartel.

Excise tax collected from the sale of petroleum products amounted to P7.34 billion from January to June this year or P2.64 billion more than the P4.7 billion collected in the same period last year, data from the Bureau of Internal Revenue (BIR) showed.

The amount paid by the oil companies in the first half of the year was P2.87 billion higher than the programmed P4.47 billion excise tax collection from petroleum products.

BIR officials attributed the increase to the higher sales volume brought about by the lower oil prices as well as the audit to be conducted by the government on the books of Petron Corp., Pilipinas Shell Petroleum Corp., and Chevron Corp.

On Wednesday, a Manila judge threatened to "arrest" the heads of the BIR, the Bureau of Customs, and the Commission on Audit for failing to "audit" the country's top oil firms.