The small business support body is submitting Freedom of Information requests to every council and health trust in Britain.
The project comes almost a year after the Government urged councils and the NHS to commit to paying their suppliers within 10 days to help counter the recession.
Statistics recently released by the Department for Business, Innovation and Skills show many Government departments are achieving this aim. But the FPB believes its members are much more likely to work for a council or health body than a Whitehall department.
The not-for-profit organisation then intends to name and shame those with poor practices, while highlighting the work of those which pay suppliers in good time.
FPB policy representative Matt Goodman said: “We believe that our requests under the FOI Act will paint a telling picture of how long small businesses across the UK are waiting for their local health trusts or councils to settle their bills.”