Thousands of teachers who marked last year's Kenya Certificate of Secondary Education (KCSE) exams have threatened to boycott the exercise this year.
The 14,000 teachers hired by the Kenya National Examinations Council (Knec) to mark last year's exams say they are still owed at least Sh1 billion.
The Kenya Union of Post Primary Education Teachers (Kuppet) wants the money paid within the next seven days or it will seek legal redress.
Secretary General Akello Misori said it was sad that months after the teachers completed their work, they were yet to be paid.
"The examiners should not be demanding payment for work done. We are giving (Knec chairman George) Magoha and the examinations council one week, failing which we shall move to court to make them pay," said Mr Misori.
Kisumu Kuppet Executive Secretary Zablon Awange said Knec should pay up or teachers would boycott this year’s exam marking.
“If Knec cannot honour its obligations, it should stop hiring teachers,” said Mr Awange.
He said Kuppet was disturbed by the payment delay nearly four months after former Education Cabinet Secretary Fred Matiang’i promised prompt payments.
Releasing the results last year, Dr Matiang'i said examiners would be promptly paid their allowances.
"We want to see the promptness in releasing the results reflected in paying examiners," said the CS at the time.
Reached for comment, Prof Magoha said he was not aware that the examiners had not been paid.
“I will confirm (if they have been paid) and if not, we will do the needful,” he said.