The Kenya Urban Road Authority (Kura) has sounded the alarm over the shrinking supply of gravel, which has seen prices rise seven times in the past decade.
Kenya's huge appetite for new roads could soon see the country start importing natural construction materials whose local supplies are getting depleted.
The country, which is East Africa's largest economy, has in recent years stepped up spending on motorways to increase connectivity and activity in an effort to make up for years of underdevelopment, pushing up demand for building materials.
Kura acting general manager in charge of planning Daniel Muchiri said the depletion of quarries might soon see the country start importing construction materials.
The recent boom in real estate has also reduced supply as Kenyans increasingly build homes in places that previously served as gravel pits.
Kiambu's Kamiti Quarries, which have over the years supplied gravel for Nairobi's roads, are almost depleted.
In Murang'a and Kisii, the gravel pits are fast being subdivided and developed into homes, reducing local supply and driving prices up.