In a footnote in its half-yearly financial statements, the aerospace group said it was working with UK, French and German export credit agencies (ECA) to resolve compliance issues raised by the irregularities, which sources have said dated back years.

"A process for the re-establishment of ECA financing has been agreed and is ongoing," the footnote said. "The group is also cooperating with the SFO."

Britain in April froze applications for government export credits for Airbus passenger jets and called in its Serious Fraud Office (SFO) after Airbus Group said it had discovered inaccuracies in applications for export support.

French and German agencies quickly froze similar support.

After a preliminary examination, the SFO typically takes several months to decide whether to launch a formal probe.

Asked whether the SFO had opened an investigation into Airbus Group, a spokesman for the agency said: "There have been discussions, but we can’t really comment further at the moment."

No major investigation has yet been announced and a spokesman for Airbus said it was not being investigated.

Earlier on Wednesday, Airbus Group said the funding was targeted to resume by the fourth quarter.

Speaking to analysts, Chief Executive Tom Enders said: "This is not just an Airbus target; this is a target for all the export credit agencies as well, including the UK export agency."

However, a person familiar with the matter told Reuters recently that much work remained to be done in establishing a transparent framework, following what some industry observers see as a temporary breakdown of trust between Airbus Group and the European export agencies.

Asked to comment on the timetable outlined by Airbus Group, a spokesperson for UK Export Finance (UKEF) said:

"UKEF continues to work closely with Airbus to understand the extent of the matter and to seek assurances about its current compliance practices in relation to overseas agents.

"As previously stated, we hope that this process can be quickly concluded and UKEF is working to resolve the matter as quickly as possible."

Export credits helped to finance just 5 percent of Airbus deliveries in 2015, down sharply from peak levels of well above a third during the global financial crisis when banks pulled back and governments stepped in to guarantee financing. The gap in funds left by the current freeze on credits has nonetheless forced Airbus to offer more customer finance this year.

(Editing by Jane Merriman/Ruth Pitchford)

By Tim Hepher and Kirstin Ridley