The minister also repeated the claim that one London-based company had suffered a security breach which cost it "£800m worth of revenue".
Many countries around the world now have their own CERT, a crucial component in the sharing of information to prevent cyber-attacks.
The government says it has allocated £860m to the UK's cybersecurity efforts.
However, figures were not available for the current budget specifically for CERT-UK, which will be based in London and will consist of a team of 55 people.
According to its website, cert.gov.uk, CERT-UK would issue an alert and appropriate guidance in the exceptional event of a critical national cybersecurity incident.
Providing advisory notices of "cybersecurity issues being detected across government, industry or academia" would be another function.
Although CERT-UK had its official launch today, director Chris Gibson, formerly the director of e-crime at global bank Citigroup, was appointed in November and work has been in progress for some months.
National Grid spokesman Steve Collins described the launch of CERT-UK as a "milestone".
It will also provide a single point of contact for co-ordinating international responses to computer security incidents - a move welcomed by other countries' cybersecurity teams.