Former prime minister Tony Abbott is considering putting pen to paper and writing a sequel to his 2009 book Battlelines, which his publisher says would make the case for the Liberal Party to return to its conservative roots.

And Mr Abbott is having a range of policy ideas costed by the Parliamentary Budget Office, in a clear sign he intends to contribute to public policy debate in the Coalition in the months and years ahead - even if it is from the backbench, and not via a return to the cabinet.

The former prime minister's publisher, Melbourne University Press chief executive Louise Adler, said she was hopeful the book would be released in 2017.

Mr Abbott told Fairfax Media on Wednesday that "it's true that my friend Louise Adler has been pestering me for a long time to write another book".