The opposition has maintained that systemic failures in the electoral agency that led to nullifying of the August 8 presidential election must be addressed before the October 26 repeat poll.
National Super Alliance leader Raila Odinga said the Independent Electoral and Boundaries Commission must respect the directives given by the Supreme Court to guarantee a fair election.
"I am not afraid of facing Uhuru Kenyatta. However, I will not go into an election until IEBC rectifies the mistakes pointed out by the court," Mr Odinga said in Nairobi.
"The baggage that can dent the credibility of the fresh poll must be addressed so that there is a level-playing ground."
The opposition leader insisted that Safran Morpho and Al Ghurair should not be contracted to supply the electronic materials and ballot papers for the election.
"There is enough time to look for alternatives," said Mr Odinga.
SUPREME COURT RULING
IEBC communication manager Andrew Limo said the agency was studying the Wednesday detailed Supreme Court ruling "and will communicate how the recommendations will be implemented".
"The chairman is reading it. It is only fair that we give him time," he told the Nation.
Siaya Senator James Orengo said IEBC owed the country a credible election.
While delivering the judgment, Chief Justice David Maraga said though the court found institutional problems in the commission, blame could not be laid on anyone.
The court nullified the re-election of President Uhuru Kenyatta on September 1, citing irregularities and illegalities.
Justices Maraga, Philomena Mwilu, Smokin Wanjala and Isaac Lenaola made the majority decision that nullified the election.
Justices JB Ojwang and Njoki Ndung'u said Nasa had not shown that there were irregularities in the August 8 election.
Meanwhile, Mr Odinga told observers that they had another chance to play their role effectively in the presidential election rerun.
In a statement to newsrooms after meeting with representatives of the National Democratic Institute and the Carter Center, Mr Odinga told the observers to be vigilant and pay attention to what the court found to have gone wrong on August 8.
FREE AND FAIR POLLS
"We believe in observation and see it as a critical part of ensuring free and fair elections. Observers should focus on the right things," Mr Odinga told the Carter Center delegation.
The lobby sent former US Secretary of State John Kerry to lead its team of observers last month.
Mr Kerry heaped praise on the IEBC "for conducting free and fair elections" despite concerns by the opposition and the civil society.
Mr Odinga said the endorsement of the election by Carter Center "is now water under the bridge and the focus should be on the coming poll".
"In the glowing compliments to the IEBC and talking of how Kenya was leading the continent in the path to democratisation despite our protests, the Carter Center went too far. But to err is human. We hope it does not happen again," said Mr Odinga.