WASHINGTON - THE female descendant of a long line of US military officers was promoted to four star general on Thursday, the first woman ever to reach the top rung of the US military.

General Ann Dunwoody accepted the promotion and command of the army's materiel command with humour and humility at a Pentagon ceremony so packed with well wishers that three star generals were standing in the aisles.

'When people ask me, Ann, did you ever think you were going to be a general officer, say nothing about a four-star, I say not in my wildest dreams,' she said.

'There is no one more surprised than I, except, of course, my husband.

And you know what they say, behind every successful woman there's an astonished man.'

Her husband, Mr Craig Brotchie, a retired air force officer, and army chief of staff George Casey, pinned the stars on her shoulders.

'Although it's taken a long time, probably longer than it should have, what's happening here today is something our entire Army can celebrate and take pride in,' General Casey said.

Before her promotion, General Dunwoody was one of only two female three-star generals in the army and six in the military as a whole.

In breaking the brass ceiling, she became one of only 21 full generals in the army. About 14 per cent of the army's active 543,000-strong force are now women.

General Dunwoody said many of her mentors and role models were men, including her 89-year-old father, a veteran of World War II, Korea and Vietnam who was in the audience.

Also at the ceremony was General David Petraeus, the US commander in Iraq, the heads of the military services, and two former army chiefs of staff.

Military women in audience shouted 'Hooah' as General Dunwoody spoke with emotion about her military family and career.

US Defence Secretary Robert Gates said General Dunwoody's blood runs 'olive drab'. Her father, grandfather and great grandfather were West Point graduates. A sister was an army helicopter pilot, and a niece piloted A-10 attack aircraft in Afghanistan.

'A Dunwoody has fought in every American war since the Revolution,' Army General Casey said.

He noted that around the time General Dunwoody entered the army after college in 1975, the army conducted a survey of attitudes about appropriate jobs for women in the military.

'The number one job at 1975 that the officers and enlisted men and women of the Army thought was appropriate for women was cook,' he said.

'And that, by 98 per cent of the men and 97 per cent of the women.'

General Dunwoody went on to become a parachute officer for the 82nd Airborne Division during the 1990-91 first Gulf War.

She rose through the army as a logistician.

The army still bars women from serving in combat infantry units.

Asked whether that should change, General Dunwoody told reporters she had no personal views on it.

But she said 'it's been my experience in my 33 years in the military that the doors have continued to open and the opportunities have continued to expand.

'And so I think, as time deems it necessary, that that review will be revisited.'

She said the generation of women who entered the military when she did in the mid-1970s 'was a generation of firsts'.

'And so I think what we see now is that generation is now reaching the senior ranks of our Army. The last brigadier general officer list had five female general officers on it.

'So the bench is deep, and the opportunities are tremendous,' she said. -- AFP