DFAT will be questioned over alleged secret approaches to foreign agencies for money to back Adani's Carmichael coal mine.

The Department of Foreign Affairs and Trade (DFAT) recently received a Freedom of Information (FOI) request for documents relating to requests for foreign government financing for the multi-billion-dollar mine and rail project.

DFAT responded, asking for more time to consider the request, as it “captured several hundred pages of documents”.

The FOI request lodged by The Australia Institute asked for all “correspondence and cables” relating to requests for foreign government financing of Adani.

It asked DFAT to provide any documents that “include or refer to any formal representations made by any Australian Government minister or official requesting or recommending consideration of financial contributions towards or involvement in these projects” from foreign government agencies in 2017.

The request included “export-import banks or credit agencies, or multi-lateral financing agencies, or foreign private sector financiers”.

DFAT asked for an extension in response, “due to complexity and volume as your request has captured several hundred pages of documents”.

Reports say a number of Australian embassies overseas have been searched for documents.

“The Australian Government appears to be helping Adani secure financial assistance and support from overseas,” said The Australia Institute's executive director Ben Oquist.

“The fact that the department has said there are several hundreds of pages relating to multiple countries and from departments in Australia … suggests there is a lot of work going on.”

DFAT said any comments on the matter would come from Trade Minister Steven Ciobo.

Mr Ciobo has confirmed an FOI request is currently being considered, but has not commented further.

“A large number of documents were potentially captured under the FOI request,” he said.

“Any documents released to the FOI applicant will also be placed on the department's public FOI disclosure log in due course.”

DFAT has also applied to the Office of the Australian Information Commissioner for an extension before releasing any documents.

Adani is seeking a $1 billion Northern Australia Infrastructure Facility loan to build a rail line linking the Carmichael coal mine to the port of Abbot Point, which it also owns.