Steve Chalke, the founder of the Oasis Trust, has launched an urgent appeal for donations towards its care of teenagers coming to the UK from the Calais 'jungle'.

The first boys being housed by Oasis, aged 16 and 17, arrived on Friday at a "safe house" in east London funded by the Christian charity. These came under the Dublin Agreement which commits the UK to housing the relatives of other refugees here.

A new tranche of young people is set to arrive today at the safe house, which is a former hostel, under the Dubs amendment which requires Britain to take in some 300 unaccompanied vulnerable child refugees.

Speaking to Christian Today, Chalke said: "Our job is to provide them with protection, care, a loving environment, food, medical help and clothing. We've put in place some therapy for them.

"These young people have been through an horrific two years – they are lonely, frightened and traumatised – they all look like sticks. They hadn't slept for 36 hours before coming to us."

Oasis has been told by the Home Office that the boys who arrived on Friday will be with them for just a few days but the charity is expecting to house them for longer.

Of the new set of children, arriving today, Chalke said: "They have no relatives to go to so they will be with us for much longer. Home Office talking to us about 6-8 weeks. It could be longer."

Oasis is providing 24-hour cover, with three shifts a day and a manager for each shift plus five support staff, along with medical staff, thereputic staff, translators and security. "We've kitted them out with clothes, pyjamas, underwear, books, medical supplies," said Chalke, a Baptist minister.

"It's the existing capacity of Oasis that meant the Home Office talked to us," Chalke said. "We were greatly helped by the fact that this week is half term – so teaching staff who would be on a half term holiday can help out. It means we had a huge number of people volunteering. We're operating on a mix of staff and volunteers – but by next week it's got to be all staff because our school staff will be back at work."

Asked about the nature of the debate in the UK, which has seen Conservative MPs calling for dental tests to check the age of the refugees, and media reports of them being older than children, Chalke said: "It's been really depressing. Some politicians haven't helped: this talk about they are not kids, they are all 30 year olds, why don't we do a dental test – I have a friend who is a professor of dentistry: he says it's ridiculous – you cannot tell a person's age from checking their teeth."

Chalke added: "All of the boys who came to us are clearly boys."

Oasis has received abuse on its Facebook page. "We have had what can only be described as xenephobic and hate-driven postings," said Chalke.

The minister, who founded Oasis more than 30 years ago, paid tribute to his staff at the charity and at his church in south London. "We feel really privileged that the Home Office approached us and talked to us and that has to do with all the hard work of so many people of the church in Waterloo – and all of the hard work of all the people in Oasis over so many years.

"Our goal is to set up a long term housing project for refugees. It's your hard work – your prayer with boots on – and engagement and involvement that creates the relationships that make these things possible."

Donations to the Oasis appeal can be made via this link.