The convention, known as the National Delegates Convention (NDC), is scheduled to take place on March 27 in Nairobi.
The meeting is expected to bring together senior leaders from across the party to discuss key issues affecting its leadership and future direction.
However, Orengo says the meeting has not been properly convened and therefore cannot be recognised as legitimate by members of the Linda Mwananchi faction.
Speaking during an interview with NTV on Saturday, the governor said the group would not participate in what he described as an illegal meeting.
“We can’t be part of it because it is an illegal NDC. It has not been properly convened, so we will not be able to attend it,” Orengo said.
According to him, the procedures outlined in the ODM party constitution must be followed before such an important gathering can take place.
He argued that if these rules are not respected, any resolutions passed during the meeting could be challenged by party members.
The planned convention is expected to attract many high-ranking officials within the party.
Organisers say the meeting will include members of the National Executive Committee (NEC), the parliamentary group, governors, county assembly leaders and representatives from various party leagues.
Delegates representing youth, women and persons with disabilities are also expected to attend the meeting to take part in discussions and decision-making.
Several key agenda items have been listed for discussion during the convention.
One of them is the ratification of a resolution made earlier by the party’s National Governing Council (NGC) concerning party leadership.
Delegates are also expected to consider another resolution from the NEC related to Article 87 of the party constitution.
Party officials say this article touches on important matters regarding the internal organisation and management of the party.
In addition, the convention will feature an address from the party leader, who is expected to speak about the party’s direction and plans moving forward.
Despite the preparations for the gathering, Orengo’s remarks highlight growing differences within sections of the party.
The Linda Mwananchi faction, which he supports, believes that certain procedures must be followed before major party meetings are held.
Political observers say disagreements over internal processes and leadership decisions are common in large political parties, especially as they prepare for future elections and strategic planning.