COTU Secretary General Francis Atwoli may have on Saturday preempted some of the key changes being pushed by top leaders in the impending referendum.
Last week, ODM leader Raila Odinga, who has been vocal in the push to have the constitution changed, said that '2019 is a must year for change in Kenya'.
"For those who doubt, I want to assure you that 2019 is the year Kenya will change. Nothing will stop us from changing the constitution. It's a must change," he said.
Deputy President William Ruto has expressed reservations towards the proposed changes, accusing Mr Odinga's team of scheming to create more leadership seats in the country.
At Lamu on Saturday, Atwoli said Kenya would likely move to a parliamentary system, which would introduce a powerful premier post like in many Commonwealth countries.
"We are going to have a referendum whether you like it or not. Nobody is going to stop it. We shall have president, deputy president, Prime Minister and two deputies," Atwoli preempted.
In the system, the presidency is likely to be ceremonial, only limited to head of State function. The Prime Minister will be the head of government.
If such a set-up succeeds, the cutthroat competition among parties is likely to resurface. The majority party in parliament would form government.