Police Monday night mounted roadblocks on roads around State House ahead of planned street protests in the city.
The officers at times inspected vehicles using the roads.
This scared some road users as they were inconvenienced for a while.
Police argued State House being a vital installation, there was a need for periodic security checks around.
Dozens of armed police officers laid roadblocks on roads leading to State House in Nairobi ahead of the planned protests.
Police were deployed with spikes at various points on major roads including State House Road, State House Avenue, Processional Way and Dennis Pritt where they briefly stopped and questioned motorists.
The officers said they were then under instructions not to allow the motorcyclists as they could be used to ferry crowds to State House for the protests.
A survey showed a heavy presence of anti-riot police on major roads and informal settlements.
They plan to trail leaders of the protests and disperse them.
This came after Azimio la Umoja leaders said their protests against the cost of living, electoral malpractices among others would resume on May 2.
More than 1,200 new police officers were brought to Nairobi to back up those already in the city.
The police said the request by the Azimio leaders to stage the protests in the city centre had been rejected because it will lead to more chaos.
The Azimio leaders say the police have no such powers to allow or not to allow meetings saying the move is unconstitutional.
The move to block some roads scared some road users who have stayed away hence rendering it counterproductive.
The leaders of the protests say they plan to leave a petition at the Office of the President and National Treasury, which are along Harambee Avenue.
But police fear the crowd might be huge and become out of control hence their move to declare the plans unlawful.
They plan to disperse any group in the city or that tries to access the city centre.
This is likely to disrupt businesses, which are already struggling.
There are reports some rival groups are planning to join police in the fight against the protesters amid fears of more chaos.