The decision was reached at State House in a meeting chaired by President Ruto and Deputy Party Rigathi Gachagua.
Embu Governor Cecily Mbarire took over as the chairperson of the party while Member of the East African Legislative Council, Hassan Omar, took over as the vice chair, replacing former agriculture minister Kipruto Kirwa who resigned from the party and joined Azimio la Umoja before elections.
The party which won the presidency, majority of seats at the Senate, and National and County assembly across the country, has been operating without a chairman for two weeks and a treasurer for over a year, including other positions yet to be filled.
Other appointments were that of Kitutu Chache North Japheth Nyakundi as the treasurer and Mwala MP Vincent Mwala as the party's organising secretary who replaces Karisa Nzai.
The new officials will serve on an interim basis ahead of national elections slated later this year.
During the August 2022 general election, the Ruto party under the Kenya Kwanza Coalition won 22 out of 47 seats in the Senate and 138 of the elected members of the National Assembly out of the 290 constituencies.
Two weeks ago, its national chairman and former Machakos senator Johnson Muthama quit the party to take up the position of a commissioner at the Parliamentary Service Commission.
Former treasurer Omingo Magara defected from the party to former President Uhuru Kenyatta's party before the elections while on May 9, 2022, UDA vice chairman Kipruto Arap Kirwa resigned from Ruto's party and joined Azimio la Umoja-One Kenya.
On Monday, Malala said he will ensure that under his helm UDA will be the biggest party since independence.
"This is going to be a party that will accommodate all views. I ask those who supported me in ANC to move with me. We want to ensure in 2027 we will have only one colour as we face our opponents," said Malala.
Former National Chairman Senator Johnson Muthama said the party was still strong, with officials at the National Executive Council that were still doing business, including a vice chair who was conducting the issues of the party after he resigned.
"The party is in stable condition. It is a movement that continues to attract support from every corner of the country. We plan to have elections in August and this will enable the party to fill all the positions with elected officials," said Muthama.
"This is the party that was formed a year before the election and won a majority of the seats. It will continue to grow in leaps and bounds in the coming years."
In a statement sent to newsrooms, the party said it had agreed on a raft of issues aimed at strengthening the party.
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NEC noted that UDA is preparing for the grassroots elections which will be conducted at polling centres across the 47 counties.
"In order to adequately prepare for this exercise, the UDA party will roll out party membership recruitment drive to enhance the registration of all those persons interested in participating in this exercise.
"The membership registration drive will run from March 1, 2023, to April 30, 2023. Online registration platform is available on https://uda.ke/site/."