NASA co-principals Musalia Mudavadi and Moses Wetang'ula have dismissed the push for a three-tier system of government as selfish.
In an apparent response to NASA leader Raila Odinga's call for the overhaul of the current system of government, they said it would be costly to establish regional blocs.
Noting that devolution faced many challenges such as corruption, he said zoning the country was not a solution.
"We should consolidate development and ensure funds to the counties are released in time. Let's address issues like police reforms and the independence of the judiciary, among others," he said at Chavakali High School during a thanksgiving for Sabatia MP Alfred Agoi, the two.
Wetang'ula said it would be disastrous to introduce another experiment before perfecting devolved governments.
Former Kakamega Senator Boni Khalwale also dismissed proposals to create 14 regional blocs. He also read mischief in a truce reached between President Uhuru Kenyatta and Raila, saying it could be a plot to have the two cling to power for a long time.
The leaders said the discussion about constitutional amendment should bring on board all Kenyans. "When we passed the constitution in 2020, it was clear some areas in it would be hard to implement. After ten years, Kenyans must seat and revisit those parts including a contentious clause on gender representation among other grey areas," said Mudavadi.
He recommended the France's hybrid government system where both the Prime Minister and ministers are answerable to Parliament. "The Executive has gone overboard and disregarded the Parliament," said the ANC leader.
Nandi Senator Samson Cherargei told Mudavadi and Wetang'ula to brace for difficult times ahead if they fail to galvanise Western and ring fence the region.