A furious Vietnamese man allegedly threw petrol bombs at his neighbour's house after being kept awake by their karaoke machine.

Nguyen Huy Ngoc, 61, was allegedly seen preparing the flammable cocktails from the third-floor balcony of his house in Hanoi, Vietnam, before firing 15 of them onto the properties below on Saturday night (November 21).

He was reportedly angry with a neighbour who was having a loud karaoke party at his house for the weekend.

One neighbour told local media: "This man is always drunk and would easily be angry over small things. He seemed normal but he is always mad."

The blaze from his Molotov cocktails spread through other houses near his target, including a power line connected his house.

After the outburst, the old man went back inside his room as if nothing happened and locked his doors while houses caught fire below.

Some of his neighbours reportedly suffered minor burns when they were sprayed with burning petrol.

Onlookers were shouting while watching the bizarre scene before calling the police to report the incident.

Officers went to his house to question him, but found that the old man himself suffered burns on his arms so he was taken by cops to the hospital.

The local police are still investigating the incident and have taken footage recorded by neighbours as evidence.

An officer from Hanoi Police said they received the reports from residents around 10:30 p.m.

He said: ''The fire happened in Trieu Khuc Street of Thanh Tri District so we immediately went there to assist with the fire department.''