Mr Doolan, a retired rear admiral and Australian War Memorial board member who has not been the subject of any previous allegations, allegedly received the car as a present at a dinner marking his retirement after seven years as president last year, Fairfax Media understands.

It has also emerged that the current national president Robert Dick and deputy president Stuart Cameron both knew Mr Doolan had received the car and other items believed to be gifts worth several thousand dollars.

The rest of the national board voted unanimously on Friday morning that if the car was a gift, it was inappropriate. It agreed to launch an investigation and also invited Mr Dick and Mr Cameron to consider their positions, Fairfax Media understands.

The league issued a statement on Friday night that read: "The national board of the Returned and Services League of Australia is to engage an external investigator to inquire into the circumstances surrounding the provision of gifts to former RSL national president, Rear Admiral (Retd) Ken Doolan AO, upon his departure from office in June 2016."

NSW president James Brown - who was elected earlier this year amid a members' backlash against the state expenses scandal - moved the motion at Friday's meeting raising the allegation of the car, it is understood.

The league's constitution stipulates that office holders are volunteers, raising questions as to whether such a gift would be in breach.

The latest revelations deepen the scandal that has embroiled the league since Fairfax Media first reported a year ago on concerns about expenses claimed by state council members. A NSW public inquiry has this week revealed explosive details about the credit card use by former state president Don Rowe, which included using RSL funds to pay off his mortgage.

Mr Doolan was national president of the league from 2009 until early 2016. He could not be reached for comment on Friday afternoon. Neither Mr Dick nor Mr Cameron could be reached for comment.

Fairfax Media understands that the claims about the gift of a car to Mr Doolan have been the subject of intense discussions over the past day by the national board at its annual general meeting in Canberra.

Sources said the gift of the car was announced at a farewell dinner for Mr Doolan in June last year.

Mr Doolan's successor as national president, Rod White, resigned this year after it emerged he was among the current and former NSW council members to have received unexplained consulting fees as directors of the league's aged care arm, RSL LifeCare.

Those payments are one of the subjects of the public inquiry being headed by former Supreme Court Judge Patricia Bergin.