The Senate will this afternoon debate and vote on the controversial third generation formula for counties revenue sharing.

The session is expected to be heated after a number of Senators from the Coast and North Eastern region vehemently opposed the formula proposed by the Senate Committee on Finance.

ODM Leader Raila Odinga on Monday urged the Senate to pass the formula which has the blessings of President Uhuru Kenyatta and his henchmen in the Senate led by Majority Whip Irungu Kangata.

However, a number of Senators whose counties are set to lose revenue after the new formula is passed have vowed to defy Odinga and vote against the formula fronted by Kangata.

There are 18 counties that will lose revenue - mainly from the Coast, North Eastern, and parts of the Rift Valley.

Narok Senator Ledama Ole Kina has urged Senators from the affected counties to soldier on even after the statement from party leader.

"Pastoralist remember the advice of our elders on this revenue share formula .... on this one we either stand with our eastern and coast brothers or we perish," he said.

"This is not about party positions but personal to us as senators from the Coastal region. If it is passed, it will further marginalize our region, which has been neglected by successive governments,” Kilifi Senator Stewart Madzayo.

Senators from Odinga's home base of Nyanza have not contradicted their party leader and are likely to vote in favour of the new formula despite earlier insisting they would stand in solidarity with their colleagues from Coast.

Nairobi Senator Johnson Sakaja, Elgeyo Marakwet's Kipchumba Murkomen, Mombasa's Mohammed Faki, and Lamu's Anwar Loitiptip some of the 29 Senators whose counties are gaining but have indicated they will oppose the new formula.

The loss of the four votes will likely not affect the new formula as it requires at least 24 Senators to vote in favor in order to pass.