Many Tokyo residents are fleeing the city and heading south, while others are hoarding supplies and lining up for hours for gas amid fears that radiation from the troubled Fukushima Dai-ichi nuclear plant will reach the city.

Residents have so far been told that radiation of 10 times the normal level has been detected in Tokyo, 240 kilometres south of the plant, but levels are still safe and there is no reason to panic.

But the reassurances haven't stopped tourists and residents from fleeing the capital, said freelance journalist Chris Johnson.

"I'm one of the last people I know to leave Tokyo," Johnson told CTV's Canada AM.

"All of my other friends left earlier. Basically anyone with small children is leaving and when I took the high speed bullet train it was just full of Japanese mothers and their babies while their husbands were still working in Tokyo today."

He said Sony, which normally has about 6,000 people working in its Tokyo headquarters, is down to a skeleton staff of about 120 people.

He said many have relocated to Osaka, including foreign journalists and the entire Austrian embassy.

At Tokyo's main airport hundreds of people lined up trying to get flights out.

"Everybody is sort of waiting and watching and fearful about the situation," he said.

Some residents remain in Tokyo

However, Johnson said many people don't have the money or means to flee Tokyo and are waiting out the crisis as best they can.

For those who have chosen to remain in the normally bustling, modern city, there was tough competition for non-perishable food items, water and gasoline.

If radiation levels increase, residents could become confined to their homes, forced to seal windows and doors to protect against the risk of radiation.

As a result, many store shelves have been cleared out of items like rice, instant noodles and bread as residents stock up on essentials.

Meanwhile, Japan has stepped up efforts to take control of the media message. The Japanese foreign ministry is increasing the number of news conferences to counter rumours and exaggerated reports, and is releasing more information in English, Chinese and Korean, Kyodo News reported Wednesday.

The Japanese prime minister's office also launched an official Twitter account on Wednesday.

Time Out Tokyo, a culture and travel website, tweeted Wednesday that it was "laughable" that some foreign media organizations were reporting that Tokyo was in a "state of panic with thousands on the run."

Flights to Tokyo cancelled

As of Tuesday some airlines began cancelling or diverting flights into Tokyo over fears of radiation.

In the U.S., the Federal Aviation Administration said it was watching the situation and was ready to reroute flights if necessary.

German airline Lufthansa has detoured its flights from Tokyo to Osaka and Nagoya, and said it would continue to do so until at least the weekend.

Air China cancelled flights to Tokyo and Taiwan's EVA Airways cancelled flights to Tokyo and Sapporo at least until the end of the month.

Air France-KLM has moved all of its crew from Tokyo to Osaka.

However, some airlines including United Airlines and Continental Airlines were continuing their Japan flight itineraries as scheduled, but said they were closely monitoring the situation.

British Airways, Virgin Atlantic and Finnair were all still flying to the Narita and Haneda airports as of earlier this week.