Anyone riding an electric bicycle in Northern Ireland without a proper licence could face a fine of up to £1,000, it has been revealed.
The Department for Infrastructure confirmed that anyone who owns one of the bikes in NI must have a motorcycle licence.
Northern Ireland is the only part of the UK where this applies.
Legislation to change the law in NI began in 2016, but cannot be completed as the assembly is not sitting.
As a result electric bikes in Northern Ireland need to be insured, taxed and registered with the DVLA.
Riders will also have to wear a crash helmet.
The police told BBC Radio Ulster's The Nolan Show that anyone not complying with the law could be liable for a fine and a minimum of six penalty points.
A disqualification is also possible, depending on a judge's view of the offence.
The bikes have small electric motors which can travel distances of between 40 and 60 miles (64-97km), and allow speeds of up to 15mph.
In the rest of the UK anyone aged 14 or over can ride electric bikes that meet certain requirements. They do not need a licence and it doesn't need to be registered, taxed or insured.
Before 1995, Electrical Assisted Pedal Bicycles (EAPCs) were treated as mopeds throughout the UK, so the vehicle had to be licensed and insured and the rider had to hold a valid provisional or full driving licence (category AM Mopeds).
In 1995, the law in England, Scotland and Wales was changed to exempt EAPCs from this requirement.
However, a similar exemption was not legislated for in Northern Ireland.
In a statement, the Department for Infrastructure said: "The department was recently approached by Sustrans NI and the Bicycle Association of Great Britain seeking clarification of the legal requirements in NI.
"They were advised that EAPCs have never been exempted from licensing or registration requirements in NI and that those selling them here should highlight to any customers wishing to use these vehicles on public roads that they must register their vehicle through DVLA in Swansea.
"Customers must also be made aware that they may have to pay vehicle excise duty and insure these vehicles.
"Anyone found riding an EAPC in NI and not complying with one or more of the legal requirement could, theoretically, face a fine between £500 and £1,000 depending on the nature of the offence. However, no prosecutions have taken place."
The police said they have been told that "until defined in law, an electric cycle should be regarded as a motor vehicle and hence requires insurance, tax, etc".
The leader of the Green Party in Northern Ireland, Steven Agnew, said that the law was "incredible".
He said the bikes are much closer to ordinary bicycles than to motorbikes.
"I will be writing to the chief constable to say to apply the spirit of the law and the spirit of the law is not to prosecute people," he said.
"It's a problem that needs to be resolved by the assembly ultimately, but the police can work on the spirit of the law, beyond the letter of the law and I'll be writing to the chief constable to make that point."
He added: "It's something that if we had a functioning assembly could be simply solved, this is something that could be brought in through secondary legislation."