Hundreds of Zimbabwean refugees are due to descend on Downing Street to urge Gordon Brown to give them the right to work.
Zimbabweans are not deported to their home country but are unable to get jobs or claim benefits.
The Prime Minister promised to review the status of Zimbabwean nationals six months ago and will be urged to "keep his word".
Jonathan Cox, from the Citizens for Sanctuary campaign, which is organising the demonstration said: "It has been half a year since the Prime Minister promised to look at what could be done for Zimbabweans.
"This demonstration will remind Mr Brown that 11,000 destitute Zimbabweans are waiting for him to keep his word.
"Our Government has been a world leader in criticising Mugabe while leaving many of those who escaped that horrific regime to languish here without hope.
"We must prepare Zimbabweans who came to Britain in search of sanctuary with the skills and experience that they will need to forge a brighter future for their country once democracy and stability are restored."
Archbishop of York John Sentamu has said more help is needed for Zimbabweans living in a "dehumanising limbo" in Britain.
Demonstration organisers say many of the refugees living in Britain could fill shortage occupations in Britain. They want internships in universities, schools and other institutions to help Zimbabweans to rebuild their country when the Mugabe regime comes to an end.
In July Mr Brown told the House of Commons that he was "actively looking" at how to support failed Zimbabwean asylum seekers. He said: "They are provided with accommodation and vouchers to ensure that they are not destitute, but we are looking at what we can do to support Zimbabweans in that situation, and we will report back to the House in due course."
