The Black Power gang has recruited Melbourne members, in the first sign it has made a push into the state, while its mortal enemy, the Mongrel Mob, has been linked to an alleged standover racket in the outer west.

Two suspected Melbourne members of the Mongrel Mob are alleged to have threatened a man by holding his head near a masonry saw when he refused to pay them $32,000.

The gangs have fought countless battles in New Zealand, raising fears that an increased push into Melbourne could result in bloodshed.

Black Power was formed in Wellington directly to counter the Mongrel Mob, whose motto is "sieg f---in heil" and whose members are often tattooed with swastikas.

Both gangs identify as similar to outlaw motorcycle gangs, with members who wear jackets with three-piece patches but are not required to ride motorbikes.

The case against two suspected Mongrel Mob members is believed to be one of the only times that members of either of the New Zealand-based gangs have been charged with serious criminal offences in Melbourne.

The Melbourne Magistrate Court heard this week that Denzil Kapene Te Amo and his father Timoti Kapene Te Amo were working as debt collectors for a masonry factory, and had agreed to split the takings 50/50 with the factory's owner.

But the pair - known as 'T' and 'Boss' - believed they were getting a raw deal and reacted with extreme violence, police say.

They allegedly stormed the masonry factory, grabbed the owner in a headlock, and bent him over a masonry cutter – a huge machine designed to cut stone – while it was still running.

It is alleged they demanded $32,000 for their services and told the victim to pay up or they would cut his head off.

One of the men then lifted the owner into the air by his neck, while the other went through his pockets, the court heard.

The father and son then allegedly bundled the owner into a car and forced him to drive to a nearby service station so he could get out cash.

The man told them he did not have a bank card, so they doubled back to the factory so he could recover it. He managed to get away and fled as one of the men chased him, yelling that he would "go back to his house and rape his wife", police said.

Both men were alleged to be members of the gang, but police said it was not believed a clubhouse had been established in Melbourne.

The pair will return to court for a committal hearing in November. No pleas have been entered.

Pictures shared on social media indicate that the Mongrel Mob has had a presence in Melbourne since 2010. Other images indicate they may have formed an allegiance with the Comanchero outlaw bikie gang.

There is less known about Black Power's push into Melbourne.

While it is also believed they do not have a clubhouse, it is understood the group have members in the Sunshine region. A member in gang colours was also seen riding in the city last month.

The Mongrel Mob and Black Power are considered to be more established in other states, but a senior law enforcement source confirmed that the gangs could recruit quickly in Melbourne given they had fewer rules governing members than outlaw bikie gangs.

However, the fact that many of the gangs' prospective members would be New Zealand citizens, and therefore likely to be deported if convicted of a serious criminal offence under the regime implemented by Immigration Minister Peter Dutton, could temper their recruitment, the source said.

In 2012, a 20-year-old considered an associate of the Mongrel Mob was jailed for stealing a car after holding a machete to the owner's throat and saying "give me the keys".

"You had became involved with a gang or group who call themselves the Mongrel Mob, which perhaps gives some idea of their collective level of intelligence," County Court Judge Gabriele Cannon said at the time.

The man told the court the mob forced him to perform criminal acts, including delivering another stolen car to New South Wales.