Home lenders have begun warning mortgage brokers they face losing accreditation if they cannot show they have registered with the financial sector's new consumer complaints authority.The Australian Financial Complaints Authority(AFCA), which is replacing three external dispute resolution schemes in the financial services industry, will begin operating on 1 November.However, some mortgage brokers have not yet registered with the new complaints handling service even though they are required to do so under the terms of their financial services licenses issued by ASIC.Most mortgage brokers were required to register by the end of August but it was revealed last month that hundreds of members of the three current schemes had not joined AFCA.Following public warnings from ASIC that non-registration with the new authority would result in licensees losing their authority to operate in the financial services industry, banks are now requesting mortgage brokers supply documentary evidence of AFCA membership.Regulators warned home lenders last month they would be in breach of lending laws if they accept loan applications originated by brokers trying to write business outside the AFCA framework.Adelaide Bank's head of broker distribution, Fons Caminiti, this week wrote to brokers across the country demanding written proof of their participation in AFCA."By now you would have received direction from the existing industry bodies of the requirement to register a membership with AFCA by 21st September 2018," Caminiti told brokers in a letter sent on Monday."As an accredited partner of Adelaide Bank, we ask that you provide evidence in the form of a copy of your new AFCA membership certificate and email confirmation that your credit representatives are also members."Caminiti said brokers were required to furnish copies of their AFCA certificates to the bank by the close of business on Friday 12 October.An Adelaide Bank spokesperson said the lender was required to confirm that all brokers it had dealings with were AFCA members."Adelaide Bank has written to brokers because it is a legal requirement that any Australian company with a financial license of any type be registered with AFCA," the Adelaide spokesperson said. "AFCA comes into effect on the 1st November 2018 and all lenders will be required to establish if companies that they do business with have registered with the new entity.     "As such, like other lenders, we will be unable to do business with any unregistered parties as they would be in breach of Australian licensing requirements."