The party was also reminded of its failure to comply with representation of ethnic diversities.
He was defeated by a newcomer, Mr William Kamket of Kanu.
MPS warn media to stop publishing stories that suggest Nasa petition is weak.
Mr Munya has disputed the election of Governor Kiraitu Murungi.
Mbugua, Irungu and Mwangi concede defeat, pledge to support successors.