Several people were reported shot, some possibly fatally, on Wednesday, and several senior opposition leaders were arrested as the Wednesday-to-Friday demonstrations the opposition has called for continue.
"The voice of the people must be heard. Our peaceful protest continues," veteran opposition leader Raila Odinga wrote on Twitter on Thursday.
The Nation newspaper reported that Odinga's Azimio party had called for its supporters to assemble at Huruma and Kangemi grounds, and Central Park in the capital Nairobi. Broadcaster NTV showed a large police deployment in anti-riot gear at Nairobi's Jacaranda grounds, scene of opposition rallies in the past.
Meanwhile, many shops in the city's central business district reopened on Thursday and traffic picked up on major roads. Schools also reopened in Nairobi, the port city of Mombasa and Kisumu, the country's third-largest city, after being shut on Wednesday.
Odinga lost last August's election to President William Ruto, his fifth election defeat in a row, and has repeatedly called for acts of civil disobedience against a government he accuses of raising the cost of living and consolidating power.
Ruto has pledged to champion the interests of the poor, but the price of basic commodities has ballooned under his administration. His government argues higher taxes are necessary to help with growing debt repayments and to fund job-creation initiatives.
At least 15 people were killed in the two previous rounds of protests earlier this month. Civic leaders have warned about sporadic incidents of apparent ethnic-based attacks in a country with a history of deadly political violence.
"We don't want a Kenya full of fighting. We don't want a Kenya of destroying people's property and roads built by Kenyans' money," Ruto said after commissioning a water project on Wednesday.
Kenyan newspapers carried a joint editorial on Thursday titled: "Let's save our country."
"President William Ruto and opposition leader Raila Odinga, in particular, owe it to themselves and to the people of Kenya to consider if they want more blood on their individual hands," part of the editorial read.