Thousands of people have been killed by last Friday’s 9.0-magnitude earthquake and tsunami, which has devastated whole swathes of Japan’s north-eastern region.

Around 450,000 people are staying in temporary shelters, while food and water remain in short supply.

In a rare televised address, Japanese Emperor Akihito said he was praying for the people of Japan and admitted that he was “deeply worried” about the nuclear situation.

Seawater has been pumped into the Fukushima Daiichi plant in a desperate effort to cool the reactors but radiation levels have surged in recent days, prompting serious health concerns.

More than 140,000 people living within 19 miles of the plant have been ordered to stay indoors but many people are trying to move further south or leave Japan altogether to avoid any risk of contamination from leaked radiation.

Lindsay Brown, International Director of the Lausanne Movement, expressed his “profound sadness” over the disaster that has hit Japan.

“We grieve at the loss of life and the unimaginable devastation being experienced by the Japanese people,” he said in a statement.

“Our prayers, and the prayers of the Lausanne family, are with our brothers and sisters in Japan.

“We pray for strength for them as they struggle to comprehend these enormous losses in light of the hope we have as believers in Christ.

“We stand with them in their hope for rebuilding and the renewal of their great nation and encourage Christians around the world to do all they can to offer comfort, encouragement and tangible support to our friends in Japan.”

The ACT Alliance of Christian development agencies said today that the relief supply needs at evacuation sites were increasing.

It said the sites were reporting a lack of food, water, electricity, health and hygiene kits, and blankets. It added that the need for stoves had become “critical” following a drop in temperatures and the arrival of snow.

ACT member Church World Service is supporting relief efforts for around 250,000 people living in 100 evacuation sites in Miyagi, Fukushima, Iwate, Ibaragi and Tochigi prefectures.

"Although Japan is considered among the most advanced countries in terms of disaster risk reduction measures, the damage caused by the unprecedented scale of this disaster is beyond imagination," said Takeshi Komino, the head of emergencies for CWS Asia Pacific.

World Vision is also responding to the disaster, with a particular focus on the needs of children. It is setting up child friendly spaces where children can go to play safely and recover from the trauma of the last week.

Mitsuko Sobata, advocacy officer for World Vision Japan, is in one of the worst hit cities, Sendai.

She described the situation there: “Last night, I visited one of the shelters housing some of the 340,000 people who have been evacuated around the city.

“Children are sleeping on cardboard with one blanket in freezing weather. It was very difficult for me to see that.”

World Vision said it was gathering relief supplies for thousands of people affected by the disaster and that a relief team was making its way today to the city of Tome, 250 miles north of Tokyo, to distribute clean water, blankets and other essentials to 4,500 survivors.

Mark Bulpitt, head of emergencies at World Vision UK, said: “The sheer scale of this disaster is as bas as anything we’ve seen globally.

“Our experts on the ground are constantly assessing the situation and will focus on the specific needs of children, many of whom will be deeply affected by this experience.”