Japan has launched a large-scale radiation survey in an attempt to reassure the public following leaks at the Fukushima plant.
Tokyo's local government is sending officials out to 100 locations including parks and school playgrounds.
Previous readings had been restricted to a single site in the city of more than 13 million.
"We were asked by mothers who are worried about the safety of their children. People want to know what radiation levels are like in their own neighbourhood," a Tokyo government official said.
Residents in Tokyo, 240 km southwest of the Fukushima Daiichi plant which was hit by the March 11 earthquake and tsunami, were alarmed when they were warned not to give babies tap water due to radiation leaks.
The warning was later lifted, but readings exceeding the government-set limit were recorded in farm products such as tea leaves grown in areas far more distant from Fukushima.
A survey this week found 0.06 microsieverts per hour of radiation at one metre above the ground in a Tokyo park, and 0.07 microsieverts per hour at 5 cm above the ground, in line with normal radiation levels in the city, the official said.
Cooling functions at the Fukushima plant, operated by Tokyo Electric Power Co, were knocked out by the 9.0-magnitude quake and tsunami, causing radiation to leak into the atmosphere and the ocean in the world's worst nuclear crisis in 25 years.
Engineers are still struggling to bring the six-reactor plant under control.