The previous Labour Government had set 2012 as the deadline for the 2Mbps network to be in place.
Culture Secretary Jeremy Hunt says he doesn't think there's "sufficient funding in place" to meet that goal.
"Last month, I announced that we were supporting a universal service level of 2Mbps as the very minimum that should be available," Hunt told an industry conference yesterday.
"I have looked at the provision the Government made to achieve this by 2012, and I am afraid that I am not convinced that there is sufficient funding in place."
"So, while we will keep working towards that date, we have set ourselves a more realistic target of achieving universal 2Mbps access within the lifetime of this Parliament."
BT also warned that it will cost billions to get fast broadband to every part of Britain.
Steve Robertson, chief executive of BT Openreach, told BBC Five Live's Drive programme that the goal could not be achieved without around £2bn in public funding.
Earlier this year a proposed 'Broadband Tax', which would have added a 50p-a-month levy to all landline phones, was scrapped at the last minute.