Sources in the party said the Narendra Modi-led government would get the support of 314 MPs in the lower house, which has an effective strength of 535 members.
The list of the 314 MPs, however, does not include Lok Sabha Speaker Sumitra Mahajan, who is also a BJP MP, they said.
The majority mark is 268.
Talking to reporters, Parliamentary Affairs Minister Ananth Kumar on Wednesday said the NDA was united and would vote against the motion.
"We are hopeful that we will get support from parties outside NDA as well. It is strange that opposition brings this motion despite the fact that the BJP got majority on its own and today NDA is ruling in 21 states," he said.
Kumar said the party has also issued a whip to its Lok Sabha members for two days and asked them to be present in the House.
In a House of 535 members, the ruling National Democratic Alliance has 313 members in the Lok Sabha, including 274 (including the Speaker) of BJP, 18 of Shiv Sena, six LJP and four SAD.
The stated strength of the Opposition is 222, including 63 of the Congress-led UPA, 37 of AIADMK, 34 of TMC, 20 BJD, 16 TDP and 11 TRS.
Lok Sabha Speaker Sumitra Mahajan today announced that the House would take up the debate (on the no-confidence motion) moved by many opposition parties on issues like special status to Andhra Pradesh, cow vigilantism, lynching, atrocities against women and Dalits and alleged dilution of the SC/ST Act, on July 20.
"The discussion will be held for the full day, followed by voting on it," she said, adding that there would be no Question Hour on that day.
Mahajan had not accepted notices for a similar motion during the budget session, which was washed out due to continued uproar by TDP, TRS and some opposition parties.
The motion was rejected by the Speaker on the ground that the House was not in order as there were continuous protests in the Well by opposition members on various issues.