Nominated MP Wilson Sossion says he will not relinquish his position as the secretary-general the Kenya National Union of Teachers.
Labour Cabinet Secretary Phyllis Kandie on Wednesday asked Mr Sossion and other 10 trade union leaders who won elective seats to vacate office.
But Mr Sossion on Thursday warned the Labour ministry and the government against interfering with trade union matters.
He accused Ms Kandie of playing politics in a bid to split and weaken the giant teachers union.
"I am not going anywhere. This is a trade union not a government entity. I am the Knut secretary-general. Let the delegates decide," Mr Sossion told the Nation.
Some of the union members who spoke to the Nation in Mombasa said they were ready to defend the ODM lawmaker.
Knut acting Chairman Wycliffe Omucheni said teachers will not be divided by the government.
"This is a ploy. Don't let it divide us. We must preach solidarity and be unified. No one will divide this giant union,” he said.
However, a section of disgruntled delegates from the Coast asked Mr Sossion to resign as Knut boss.
The delegates, who are aligned with former Mudzo Nzili, former Knut chairman who was forced on leave, said they would push until Mr Sossion vacates office.
"We agree with the gazette notice. We want him out," said Kitu Gwengwele, Knut Coast spokesman.