Showdown looms as both Azimio La Umoja-One Kenya and Kenya Kwanza are claiming majority.
The parties have already picked members for majority leader, their deputies and deputy majority whip.
Kenyans will be watching whether Wetang’ula’s relationship with Kenya Kwanza will inform his decision, when members reconvene later this month.
Wetang’ula promised to deal with the contest in an impartial manner, assuring both parties that he will arbitrate on the matter in a fair and unbiased way.
Lawyer Ken Echesa said deciding who is the majority in the August House will be a litmus test for Wetang’ula.
“He is an advocate of the High Court with many years of experience. He has his legal career and integrity to protect. It will be very unfortunate if he makes a political decision,” Echesa said.
“It is time to invoke wisdom as a leader, disregard political interests and pressure and make a decision that will unite Parliament more than divide it.”
The advocate said the Speaker, if he wants to make a decision that is objective and constitutional, must write to Office of the Registrar of Political Parties to ascertain where every member, party belongs.
The Azimio la Umoja-One Kenya coalition agreement brought on board 26 political parties and bars any signatory from exiting six months to the general election and three months after the polls.
Azimio boasts of 165 members while Kenya Kwanza has 160.
However, UDM, Kenya Union Party and MDG have since aligned themselves with Kenya Kwanza, giving the alliance a majority.
Ten out of the 12 independent MPs have also aligned themselves with Kenya Kwanza.
Azimio leaders argue that their affiliates who have since crossed over to President William Ruto's side are still constitutionally bound to the political formation.
Ruto has laughed off claims by the Azimio that they command a majority in the National Assembly.
He said it is ludicrous for Azimio to claim that it controls a majority in the August House, yet they could not get enough votes to install their candidate as the speaker.
The President spoke at a Kenya Kwanza parliamentary group meeting in Naivasha on Saturday.
Kericho Senator Aaron Cheruiyot argues that Azimio did not did not field any candidates for parliamentary positions in the August 9 poll and therefore cannot be the majority.
“Azimio should cease purporting to be the majority party in the National Assembly. ODM and its other willing partners are the minority side by fact and law,” he said.
Echesa said it is unfortunate that the matter will be surrendered to the speaker, who was politically elected and may end up making a political decision.
“It is clear that in the National Assembly, the majority coalition party is Azimio-One Kenya Alliance. But if we look at it as parties or coalition of parties, then UDA has the majority of members,” he said.
“In the National Assembly, it is clear that Azimio has the majority of members but the situation can change even tomorrow if some member parties procedurally defect to Kenya Kwanza and give them the legal majority.”
The advocate said parties should leave coalitions in a manner and procedure that is provided by the law.
“You cannot join a coalition through an elaborate process and then leave through a road declaration,” he said.
Jubilee secretary general Jeremiah Kioni also says Azimio is the majority in Parliament.
“As per the law we are the majority in the National Assembly and there is no debate about it,” he said.
The former Ndaragua MP said it would be regrettable if the speaker will rule otherwise.
Wiper leader Kalonzo Musyoka said the coalition legally and legitimately commands a majority in the National Assembly.
He spoke while addressing an Azimio parliamentary group meeting on Saturday.
"For the avoidance of doubt, the Azimio OKA coalition party is legally and legitimately the majority coalition in the National Assembly. This is not a matter for determination by any individual or office,” Kalonzo said.
Azimio picked Ugunja MP Opiyo Wandayi to take up the majority leader position and Kathiani MP Robert Mbui as the deputy majority leader.
The coalition further settled on Suna East MP Junet Mohammed as the majority whip with nominated MP Sabina Chege as his deputy.
Kenya Kwanza coalition has picked Kikuyu MP Kimani Ichungwah as the majority leader and Kilifi North MP Owen Baya as his deputy.
South Mugirango MP Silvanus Osoro will be the coalition's majority whip and will be deputised by Marsabit Woman MP Naomi Waqo.
(Edited by Bilha Makokha)