The search for original pieces of music is to become the focus of the London 2012 Olympic Games arts programme.
New Music 20x12 hopes to discover 20 new works in any musical style, each lasting 12 minutes, to be part of the Cultural Olympiad.
They will then be broadcast on BBC Radio 3 and may also feature at official events linked to the London Olympic Games.
The work, from a UK-based composer, must be submitted by 1 October.
Each piece will premiere in 2012 and receive at least two additional performances.
The chosen composers, ensembles, festivals, music organisations or musicians will also get financial support and help with professional development.
A panel of experts chaired by Roger Wright, controller of BBC Radio 3 and director of the BBC Proms, will then cut the entrants down to a top 20.
Cultural Olympiad director Ruth Mackenzie described New Music 20x12 as "a wonderful opportunity for composers and audiences to celebrate 2012 together".
Mr Wright said: "Projects such as New Music 20x12 will showcase the exceptional talent and creativity of the UK's musical community, and we're delighted to be able to support them on BBC Radio 3."
It is the brainchild of private patrons David Cohen and Jillian Barker and is backed by funding body the PRS for Music Foundation in partnership with the BBC, London 2012 and Sound and Music.