The Bharatiya Janata Party invited its other ally, the Lok Janshakti Party (LJP) and its chief, union minister Ram Vilas Paswan, for the meeting.
"RLSP was not informed about the meeting of National Democratic Alliance leaders," party spokesperson Manoj Lal Das Manu said.
He said Kushwaha was touring Banka and Jamui districts and state party president Arun Kumar was in Gaya district.
"Both Kushwaha and Arun Kumar are in Bihar but were not invited to attend the NDA leaders' meeting," the spokesperson said.
An RLSP leader close to Kushwaha told IANS that BJP leaders in Bihar were "unhappy" as the party decided to project Kushwaha as the NDA's chief ministerial candidate.
Soon after the RLSP's decision, the BJP made it clear that only it could decide the leader for the top post.
The LJP also said it will support the BJP's move for the chief minister's post. It said Paswan was not a contender.
Sources said the BJP plans to contest 150 of the 243 assembly seats, while the remaining seats will be given to its allies -- LJP, RLSP and new ally Hindustani Awam Morcha (HAM) of former chief minister Jitan Ram Manjhi.