Police said loaded trucks are stranded at Mao on the borders with Nagaland and at Jiribam on the borders with Assam.
However, inter-state passenger vehicles are being allowed to pass without restriction.
Supporters came out in the various hill districts to enforce the blockade, particularly at Kangpokpi area in Senapati district, police said adding there was no report of any untoward incident from any part of the state.
They are protesting against the process of implementation of Inner Line Permit system in Manipur through conversion of three ILP-related bills into Acts with the assent of the President.
The three bills were passed unanimously in August last year by the state assembly after a two month-long agitation to protect the indigenous people from illegal immigrants in the state, including those from neighbouring Myanmar.
The agitators are also protesting against the June 7 clash between Delhi police and Manipur Rifles personnel and tribal protestors from the state who had convereged at the gates of Manipur Bhawan at Chanakyapuri at the national capital. Twenty five people, including police officers, were injured in the incident.
