Australian Christians have been called on to intervene " in prayer " as a crisis faces Aboriginal churches.

The call coincides with the launch of One Land, One Saviour, a new book on ministry among Aboriginal people in Arnhem Land.

The book is a collection of essays by 13 contributors, who between them represent more than 300 years service among Aboriginal people.

Its release comes at a significant time as recent developments have put Aboriginal issues back on the political agenda, and back in the public consciousness.

“Part of the solution is a four-letter word " jobs” says co-editor Steve Etherington (pictured), who has 30 years of experience in the Top End.

Dr Etherington says the drift of Aboriginal people to urban settings is accelerating and without employable skills, more demeaning dependency is the prospect.

The CMS veteran says Aboriginal Christians witness and minister in a world of profound and bewildering change.

"There's no doubt Aboriginal churches are in crisis and prayer is urgently needed.'

In May 2007, Kriol speakers celebrated the publication of the first complete Indigenous Bible, and August 27, 2008 marks the 100th anniversary of the first CMS mission to Aboriginal people in the North.

During that century government policy has gone full circle, from protection to assimilation to self-determination and " though no politician says it openly " back to assimilation.

The remote communities of Arnhem Land, originally intended as pathways to mainstream Australian life, have turned into violent, dysfunctional prisons.

Steve Etherington will be the keynote speaker at a dinner in Sydney on Saturday to launch the book and celebrate CMS missionaries' 100 years of serving Aboriginal people.