Azimio leader Raila Odinga reminded President William Ruto that he has until Wednesday midnight to respond to their grievances which were issued at Jeevanjee gardens in Nairobi.
Speaking on Tuesday, Raila said that failure to honour the demands, Azimio will proceed with mass action on Thursday.
"We want you to wait for the time, the deadline is tomorrow (Wednesday) at midnight. So you will hear from us on Thursday," he said.
Raila on February 22, gave the Ruto administration a 14-day ultimatum to address his concerns about the high cost of living, electoral injustice, and skewed sharing of state jobs.
Raila had asked his supporters to stand firm saying upon the expiry, street protests will begin if Ruto fails to heed the demands.
Last week, Raila spelt out three demands the President should meet for them to have any talks.
Raila said Ruto must first agree to open the Independent Electoral and Boundaries Commission (IEBC) servers.
He went on to say that the head of state should also stop the ongoing recruitment of the IEBC commissioners.
The former Prime Minister added that Ruto must ensure the cost of living comes down because Kenyans are suffering.
The opposition chief has been leading a series of anti-government rallies countrywide.
Raila has held anti-government rallies in Kamukunji, Jacaranda and Jevanjee gardens in Nairobi.
He has also held rallies in Machakos, Kisumu, Busia, Kisii and Kakamega.
Despite the rallies, Ruto said he will remain unshaken and continue serving Kenyans.