Hackers claim they have broken into the computer system of the Large Hadron Collider (LHC), the mega-machine designed to expose secrets of the cosmos, British newspapers are reporting.

A group calling itself the Greek Security Team left a rogue web page mocking the technicians responsible for computer security at the giant atom smasher as "schoolkids", the Times and Daily Telegraph reported.

The hackers vow they have no intention of disrupting the experiment at the European Organisation for Nuclear Research (CERN) on the Swiss-French border, they just wanted to highlight the flaws in the computer system's security.

"We're pulling your pants down because we don't want to see you running around naked looking to hide yourselves when the panic comes," they wrote, according to the Daily Telegraph.

The hackers claim to have gained access to a website open to other scientists on Wednesday (local time) as the LHC passed its first test with flying colours, the reports said.

They appear to have tried to gain access to the computer system of the Compact Muon Solenoid Experiment, one of the four detectors that will be analysing the progress of the experiment.

James Gillies, a spokesman for CERN, told the Times says there does not seem to be any harm done.

"We don't know who they were but there seems to be no harm done. It appears to be people who want to make a point that CERN was hackable," he said.

Scientists have hailed the success of the start of the experiment in the Large Hadron Collider, the 27-kilometre circular tunnel in which parallel beams of protons will be accelerated to nearly the speed of light.

Superconducting magnets will then steer the counter-rotating beams so that strings of protons smash together in four huge laboratories, fleetingly replicating the conditions that prevailed at the Big Bang that created the Universe 13.7 billion years ago.

- AFP