document: The growing problem needs "an urgent response" coordinated by the Home Office, NAO head Sir Amyas Morse said.
  Almost two million cyber-related fraud incidents were estimated to have taken place last year, it added.
  The Home Office said government, the police and industry were working together to tackle the problem.
  Sir Amyas said the Home Office, while not solely responsible for tackling the issue, was the only organisation that could oversee the system and lead change.
  The Home Office's Joint Fraud Taskforce, which was launched in February 2016, was a positive step "but there is still much work to be done", he said.
  "At this stage it is hard to judge that the response to online fraud is proportionate, efficient or effective."
  Analysis: BBC home affairs correspondent Danny Shaw
  According to the Office for National Statistics, fraud is now the most commonly experienced crime in England and Wales, with most offences committed online.
  But the National Audit Office says only one in every 150 police officers specialises in fraud - and it doesn't even feature in a third of the policing plans issued by local police and crime commissioners.
  The NAO also criticises a Home Office taskforce set up last year to tackle online fraud, saying it's too focused on banking, lacks proper governance and hasn't established measures for its performance.
  The Home Office says the taskforce is making a positive difference but it acknowledges there's more to do.
  In the year to 30 September 2016, the Office for National Statistics estimated there were 1.9 million cyber-fraud incidents in England and Wales, or 16% of all estimated crime incidents.
  Online fraud includes criminals accessing citizens' and businesses' bank accounts, using their credit card details, or tricking them into transferring money.
  The report said: "Fraud is now the most commonly experienced crime in England and Wales, is growing rapidly and demands an urgent response.
  "Yet fraud is not a strategic priority for local police forces and the response from industry is uneven."
  The Home Office said that tackling online fraud "demands a collaborative and innovative response to keep pace with the emerging threat", which is why it had launched the Joint Fraud Taskforce.
  Improved data-sharing between banks and law enforcement had closed thousands of accounts linked to fraud, it said, adding that it was working with Financial Fraud Action UK on its Take Five to Stop Fraud awareness campaign.
  Tom Ironside of the British Retail Consortium said: "The retail industry strongly supports a much closer partnership between the government, law enforcement and industry to tackle online fraud."
summary: Online fraud has been "overlooked" by the government, police and business, according to public spending watchdog the National Audit Office.