The small business commissioner Paul Uppal, who was appointed in October by the secretary of state for business, will handle the new service.
Uppal is a former Conservative MP for Wolverhampton South West who has 20 years of experience as a small business owner in the real estate sector and will be based in Birmingham.
He will be handling complaints by SMEs about unfair and late payments.
Using the commissioner’s website, which is now available, SMEs will be given guidance on how to “check, chase and choose” how to deal with payments problems, including checking if the right information has been provided to the right people, chasing effectively when a payment is overdue and choosing how to take action, including the option of submitting a complaint.
Small business minister Margot James said the service will empower small businesses to take action if they are paid late, and potentially delivering a £2.5bn annual boost to the economy.
Mike Cherry, national chairman of the Federation of Small Businesses, welcomed the news, pointing out that 30% of payments to small businesses are late and the average value of each payment is £6,142.
He said the commissioner is "crucial to turning the tide on this late payments culture. FSB will be encouraging small businesses affected to use the service, and we hope then to see clear actions taken to tackle the worst examples of supply chain bullying. Success will be a UK economic culture where a business that does a job promptly, is paid promptly.”