The controversial campaign, which has been descirbed as offensive and insensitive, asks immigrants how hard their lives are in Scotland and says: "Let us help you go home."
It is being tested in Glasgow, where the main public inquiries office of UKBA in Scotland has been plastered with images of aeroplanes, while the centre's seats are branded with the slogan: "Ask about going home."
One poster, apparently showing a person sleeping rough on the streets, states: "Is life here hard? Going home is simple."
Another shows a photo of an aircraft and says: "The plane can take you home. We can book the tickets."
The campaign is running at the UKBA office in Brand Street, Glasgow, and the reporting centre in Hounslow, west London. It started on July 29 and will run until October 4.
It was defended by the Home Office as part of a policy to provide sensitive advice and assistance to help failed asylum-seekers return home with dignity, but critics say the office is also used by asylum-seekers still in the system.
However, Tom Harris, MP for Glasgow South, described the pilot as "political posturing" and criticised the way it asked asylum-seekers about their desire to go home.
He said: "This is crazy. If someone has applied for asylum and is pursuing that then the question has already been answered.
"This is all about pitching to particular people in Britain, not asylum-seekers. Their actual target is the voters in the next European elections. It is a cynical ploy which will only result in asylum-seekers feeling very vulnerable. It is utterly pointless and incredibly insensitive.
"Private letters to asylum-seekers whose claims have failed already explain that there is help available if they do wish to leave the UK."
The campaign follows the controversial "Go home or face arrest" vans debacle earlier this summer which resulted in the Home Office being persuaded to drop its campaign following cross-party criticism. The Advertising Standards Authority is investigating those posters.
Responding to the Glasgow campaign, David MacLachlan, minister of Langside Parish Church, said: "I am horrified by this. It is so, so offensive. After the controversy of the 'go home' vans in London they are purposefully doing this in a room where general members of the public cannot go.
"There may be bogus asylum-seekers in the system but they are unlikely to be reporting to a centre. Most are genuine and come from incredibly frightening situations. These are the most vulnerable people in our society and it is appalling to treat them like this."
James Dornan, SNP MSP for Glasgow Cathcart, said: "I condemn this and urge them to reconsider this so-called pilot and take their extreme tactics out of Scotland."
John Wilkes, chief executive of the Scottish Refugee Council, said: "We are very concerned about the appropriateness of new signage in the Home Office reporting centre in Glasgow.
"Voluntary return is just not an option for many refugees who are from war-torn countries such as Syria, Iran and Eritrea as they would face certain persecution and a real threat to their lives. One young asylum-seeker burst into tears when he saw the message about going home and seeing family and friends again. He has no idea if his family are alive or dead.
"Using blunt communications to suggest that going home is easy is insensitive and inappropriate and can send the wrong messages to people about whether their claims will be treated objectively and fairly."
UKBA said the people attending the office had had claims turned down or had breached their conditions - a point strongly disputed by the Refugee Council which says this office is frequented by asylum-seekers at different stages in the process.
A Home Office spokesman said: "Those with no right to remain in the UK should leave voluntarily. These posters are designed to ensure people know we can provide sensitive advice and assistance to help them return home with dignity.
"We also continue to work closely with community groups who welcome the opportunity for someone who is not here legally to leave the country of their own accord."