An interactive map offering detailed crime statistics on every street in England and Wales appeared to crash hours after its launch today.
Users in London, Yorkshire, Humberside and Manchester were unable to access the detailed online map.
Those attempting to visit the site, http://maps.police.uk/, were shown an automated message saying it was temporarily unavailable.
The teething problems surfaced as Home Office minister David Hanson officially unveiled the website during a visit to a regeneration project in south west London.
He was joined by National Policing Improvement Agency (NPIA) deputy chief executive Steve Mortimore, whose colleagues drew up the map.
The website aimed to offer members of the public unprecedented access to information about crimes taking place in their neighbourhood.
The national map follows on the heels of regional versions created by the 43 forces across England and Wales.
The sites have been widely regarded as a success with some registering more than 50,000 visits per month.
In a statement, Mr Hanson said giving people access to more information about crime should improve their confidence in policing.
He said: "We know the public want this information, which will allow them to hold the police to account and help create an even more responsive and effective service."
Mr Mortimore said: "Fear of crime is known to outstrip the reality. The crime map will give people the facts about local crime and what forces are doing about it."
Users should be able to access figures on levels of burglary, robbery, violence, vehicle crime and anti-social behaviour.
They can also compare one area against another and compare figures against the same period the previous year to see if crime is getting better or worse.
The website also offers messages from senior officers and links to local policing priorities and information about forthcoming crime-fighting events.
A Home Office spokesman said: "The high level of public interest in the new national crime map has put temporary pressure on the website.
"Urgent work is under way to resolve this and the website should be working again shortly."