The number of Australians caught up in the deadly terror attack in London has risen to four.
Prime Minister Malcolm Turnbull says there are "very real concerns" for two of the injured.
"We know of two Australians physically injured, one a woman recovering in hospital and another man returning to Australia," Mr Turnbull said.
He says the government is seeking to find more information about the two other Australians involved.
"We have been in touch with their families as we seek to find greater confirmation".
Seven people have died after two attacks on Saturday night London time.
A van ploughed into pedestrians on the London Bridge before a stabbing rampage broke out.
Two Australians were stabbed.
Darwin Electrician Andrew Morrison was stabbed in the neck while leaving a London Bar on Saturday night.
He has received stitches for his neck wounds and is in a stable condition.
Brisbane woman Candice Hedge remains in hospital overseas, recovering from a cut to the throat.
Ms Hedge was working at a bar at the Borough Markets with her boyfriend Luke when she got caught up in the attack.