Eight organisations have agreed to campaign for the first Missing Persons Awareness Month.
Seven events have already been arranged in an ambitious attempt to maintain interest in the issue of missing people throughout May.
The coalition includes six charities: the National Missing Persons Helpline, the British Red Cross, The Salvation Army, International Social Service, NORCAP and Reunite. The police and the Association of British Investigators are also involved.
Charities have decided to build on their previous collaborative efforts that revolved around National Missing Persons Awareness Day on 15 May.
Sarah Miller, spokeswoman at the Salvation Army, said: "We do feel there is enough interest to sustain it throughout the month. How people can just disappear is something that fascinates the public and the media.
"We are aware that a lot of people don't realise we operate in this area and we are desperate to get the message across that we do. Working together should also raise awareness of the smaller groups that offer more specialist services," she said.
The awareness day on 15 May will continue to be a focal point of the campaign, which begins on 1 May with a photographic exhibition organised by the National Missing Persons Helpline.
The Red Cross, which provides an international tracing service for relatives separated by conflict, is planning a week of events from 4-10 May. International Missing Children's Day, a US institution, will be flagged up on 25 May.
Jessica Prasad, spokesperson at the missing persons' charity, said: "The danger with having just a single day is that if there's a big news story that day, it gets pushed off the agenda.
"A lot of charities are involved in many activities about missing people and the week will reflect that."