The intensified Royal Malaysian Customs and Inland Revenue Board (IRB) tax collection efforts must not let those in high places off the hook, said PKR Youth vice chief Tan Kar Hing.

In particular, said Tan, the two agencies should look into allegations that Prime Minister Najib Abdul Razak's paid RM9.5 million payment to senior lawyer Muhammad Shafee Abdullah.

"I would like to remind the customs and IRB to apply the same principle and be firm with regard to the transaction between Najib and Muhammad Shafee to see whether there is any under declaration of taxes, be it individual or company or whether it is tax exempted.

"If the government can trace businesses and companies that were problematic (with regard to taxes), surely the government agencies can also trace the RM9.5 million and establish whether it should be taxable," Tan said in a statement today.