Postdoc before PhD completion I am in a situation where my PhD funding runs out in 5 months and I need to have secured a job regardless of whether I have submitted due to having a family. 

Although I think I may be close to submitting by then, it may take longer. Is it worth applying for postdoc positions or would universities not consider you until you have completed the PhD? I assume that the pass rates of PhDs are very high if the candidate has got to the submission stage. 

Edit: This question is aimed at the people that are are the submission stage but haven't yet defended their thesis. It is not a question asking if I can get a post-doc without a PhD.
Groups seeking postdocs will absolutely consider you as an applicant before you have completed your PhD. They will, however, want to be certain that you have completed the entire process and all its requirements prior to officially beginning your new job, as the comments above have said. Be as honest with them as possible about when you expect to finish.

Universities will vary in terms of how they expect you to prove you've completed your PhD: some will accept official letters while others will want a photocopy of your physical degree (I was asked for the latter and found it rather, er, surprising). Luckily, none of that is likely to happen during an interview.