Prime Minister Bill English says a New Zealander was hospitalised after being caught up in the blast on the London tube.
On Friday morning (local time) a homemade bomb went off on a packed rush-hour commuter train in London, engulfing a carriage in flames.
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"We've been advised that there's one Kiwi affected," Mr English said on Saturday.
"The most recent advice I've had in the last few hours is that this person has been to hospital, had treatment, and has been discharged. So it's great news that a Kiwi who's caught up in this attack is not seriously injured on the face of it.
"But for Kiwis who are in London, look I think it's a place that's mastered the art of being on high alert while they go around their daily life."
A spokesperson for the Ministry of Foreign Affairs and Trade has confirmed it is helping with the situation.
"The New Zealand High Commission in London is providing consular assistance to the family of a New Zealander injured in the incident at Parsons Green underground station.
"Due to privacy considerations, the Ministry of Foreign Affairs and Trade will not provide further information."
At least 29 people have been injured in the attack.
Some suffered burns and others were injured in a stampede to escape the station, one of the above-ground stops on the underground network, but health officials said none were thought to be in a serious condition.
"We now assess that this was a detonation of an improvised explosive device," Britain's top counter-terrorism officer, Mark Rowley, told reporters.
Pictures taken at the scene showed a slightly charred white bucket with a supermarket freezer bag on the floor of one train carriage. The bucket, still intact, was in flames and there appeared to be wires coming out of the top.
Police said a hunt involving hundreds of detectives backed by the intelligence services was under way to find out who was responsible. Mr Rowley declined to say if the suspected bomber had been on the train, saying it was a live investigation.
Islamic State claimed responsibility through its news agency, Amaq.
Reuters / Newshub.