The Comptroller-General of the Nigerian Customs Service, NCS, Hameed Ali, has told the Senate that he will not appear before it on Wednesday as expected.
In a letter written to the Senate on Tuesday, Ali said he had to attend an NCS meeting.
But the Senate Leader, Ahmed Lawann said that reason was not tenable.
The customs boss was summoned last Thursday over the planned clampdown on vehicles without duty payment.
In its resolution, the Senate said Mr. Ali must appear in appropriate Customs uniform which he has not been publicly seen to have worn.
Ali had hit back at the Senate, asking the lawmakers to show interest in his work not his dress.
In his letter, he said he had to attend an NCS meeting; but the Senate Leader, Ahmed Lawann said that reason was not tenable.