Teams of security staff accredited by the police are to be based at three Channel Tunnel Rail Link (CTRL) stations when the line is completed.
Eurostar trains will run to St Pancras when the link is completed
They will be based at Ebbsfleet, Kent, and St Pancras and Stratford in London, when the high-speed link between London and Europe comes into operation.
Staff will act under the Railway Safety Accreditation Scheme under which people and firms are vetted by police.
Rail minister Derek Twigg said safety and security remained a priority.
He said the partnership between rail firms and the police showed how the industry could work together to tackle crime and anti-social behaviour on the railway.
CTRL operator London & Continental Railways (LCR) and Southeastern have signed up for the scheme.
Security staff and their employers will be vetted by the police and trained to standards set down by the Association of Chief Police Officers.
The second and final stage of the CTRL is due to be completed next year.
The high-speed link has international stations at Ebbsfleet and Stratford and the Eurostar London terminal will move from Waterloo to St Pancras.
Stephen Jordan, managing director of LCR's stations and property division, said: "The safety of our passengers and staff is paramount.
"We remain on schedule to complete Britain's first high-speed line and the first major new railway in a century.
"It is an investment we fully intend to protect."