Kenya Kwanza Alliance governor candidate Johnson Sakaja is the most preferred candidate with 39 per cent of the vote, an opinion poll by Infotrak shows.
The poll shows that Sakaja, Edwin Sifuna, and Esther Passaris would win the seat for Nairobi governor, senator, and female representative respectively if elections were held today.
24 per cent number of voters are unsure of who they will vote for.
Sifuna, the Secretary-General of the Orange Democratic Movement, is leading in the race for the senate with 44 per cent, while Margaret Wanjiru, the United Democratic Alliance (UDA) candidate, is in second place with 12 per cent
Passaris, the ODM candidate, is in the lead with 46 per cent of the vote, followed by Millicent Omanga, the UDA candidate, with 20 per cent.
20 per cent of respondents are still unsure and 5 per cent did not respond.
Agnes Kagure, an independent candidate, received 0.4 per cent of the vote in the survey of 1,024 Kenyans across the 17 seats in Nairobi, according to Infotrak.
24 per cent of those surveyed indicated that they were unsure.
The same poll also shows Azimio presidential flag bearer Raila Odinga and his running mate Martha Karua are the most preferred candidate in Nairobi county with a rating of 49 per cent if elections are held today.
According to the poll, his closest rival, Kenya Kwanza Alliance flagbearer Deputy President William Ruto, and his running mate Rigathi Gachagua came second with a rating of 30 per cent.
The Roots party candidate George Wajackoyah and Justina Wamae received 5 per cent of the vote, while David Waihiga and Ruth Mutua of Agano received only 0.3 per cent.
Fifteen per cent of additional respondents did not express a choice for the top job.
The survey was conducted between 2-3 July through Computer Assisted Telephone Interviews.