The Church of England’s pension fund has admitted it invests in one of Wonga’s key financial backers, the Financial Times (£) reported.
The fund invests in Accel Partners, a US venture capital firm that led the fundraising for Wonga in 2009, the report states.
A Lambeth Palace spokesperson said: “We will be asking the Assets Committee of the Church Commissioners to investigate how this has occurred and to review the holding in this pooled investment vehicle.”
The Archbishop of Canterbury has promised to take on pay-day lenders and put them out of business.
The Most Rev Justin Welby has criticised Newcastle United's primary sponsor - Wonga - for charging high rates of interest. He said the Church of England wants to "compete" it out of existence.
Newcastle striker Papiss Cisse has agreed to wear the logo of sponsor Wonga on his shirt.
The 28-year-old Muslim had refused to display the pay-day loan company's branding on his kit because earning interest is forbidden by Islamic Law.
However, after several weeks of delicate negotiations, the Senegal international and the club have now found a solution and the player, who missed the club's pre-season training camp in Portugal as a result of his stance, will return to the fold.
The Church of England's Head of Mission and Public Affairs says the time the Archbishop of Canterbury spent in cities including Durham has influenced his decision to tackle pay-day loans companies.
Rev Dr Malcolm Brown said: "This is a man who has worked in a lot of major cities in the country - Coventry, Liverpool, Durham.
"He wasn't in Durham very long but he found out a great deal about it and that's been a major factor in the way he's approached the whole question of finance, banking and the way people work with money."
Wonga has responded to the Archbishop of Canterbury's claims that the Church of England plans to go head-to-head with pay-day lenders.
Errol Damelin, founder and Chief Executive of Wonga, said:
The Archbishop of Canterbury signs the credit union application. The Most Rev Justin Welby helped launch a new credit union for clergy and church staff, in an attempt to tackle pay-day lenders.
- The Most Rev Justin Welby read law and history at Trinity College, Cambridge and began his career in the oil industry based in Paris and London, where he worked on West African - mainly Nigerian - and North Sea projects.
- He became a group treasurer in a company called Enterprise Oil, before resigning in 1987 after 11 years in the industry to train for the Anglican priesthood.
- He has also served on the parliamentary Banking Standards Commission.
Conservative politicians have been voicing their support of the Archbishop of Canterbury's plans to provide an alternative to payday lending, on Twitter.
- Credit unions are small non-profit financial organisations set up by members with something in common to benefit their community.
- That common factor may be living in the same town, working in the same industry (for example, the Police Credit Union) or belonging to a particular trade union.
- Roughly 500 credit unions cover the UK offering loans, savings and current accounts to their members. A few even offer mortgages. Almost a million Brits are members.