All Opposition leaders and officials will hold a rally in Nairobi's Dandora area on Sunday as part of efforts for justice and accountability.
The rally will take place at Jacaranda grounds, NASA principal Moses Wetang'ula (Ford Kenya) told the press on Wednesday.
The Opposition hit the ground running with campaigns after the Supreme Court nullified President Uhuru Kenyatta win in the August 8 presidential race.
IEBC had announced that the President defeated ODM leader Raila Odinga by more than 1.4 million votes.
Uhuru's Jubilee Party has also been campaigning and IEBC set October 15 as the last date for rallying voters.
A NASA rally took place in Kibera on Tuesday and key was the demand for IEBC Chief Executive Office Ezra Office to leave office.
Raila also said the commission treated them with contempt during their meeting earlier in the day and handed them a "strange" document they had never seen before.
Wetang'ula, who is Bungoma Senator, further denied claims NASA chief campaigner Musalia Mudavadi (Amani National Congress) had left the coalition.
The other member is Deputy President candidate Kalonzo Musyoka (Wiper). Chama Cha Mashinani's Isaac Rutto returned to the ruling coalition after losing the Bomet Governor seat to Joyce Laboso.
Former Meru Governor Peter Munya lasted barely a day in the coalition before meeting and announcing he will work with Uhuru and DP William Ruto.
A letter shared on social media carried the claim that Mudavadi had resigned. But Wetang'ula said the National Super Alliance is intact and that members are preparing for the hot contest between Uhuru and Raila.
"NASA is intact and it is moving to ensure we take our rightful positions ahead of the election which needs to be devoid of irregularities."
The Senator said the social media claims are baseless propaganda by their rivals.
"NASA does not deal in fake news...there are some people peddling lies on social media."
'BOYCOTT PARLIAMENT PROCEEDINGS'
The Opposition further resolved to snub Parliament and skip the formation of critical House committees.
The Ford Kenya leader noted the bicameral Parliament as currently constituted is illegal.
"Our MPs will not be party to any parliamentary proceedings or House committees because the Houses as currently constituted are devoid of any legality."
Wetang'ula said they will treat the committees as Jubilee groupings. The President and Jubilee legislators have said they will carry on with business even without their NASA counterparts.
On Tuesday, most NASA lawmakers and the Judiciary boycotted Uhuru's address for the opening of the 12th Parliament .
Only one NASA legislator - Webuye East's Alfred Sambu of Amani National Congress - attended the function.
The Opposition legislators had threatened to stage a “mass no-show”. Minority whip-designate Opiyo Wandayi (Ugunja) led calls to “empty-chair” Uhuru, saying they cannot sit and listen to a lame-duck President.
“We as members of NASA, and myself for that matter, find it politically untenable to sit in Parliament and listen to a person against whom my party leader is competing,” he said.