Jana Bennett, director of BBC Vision, said that the corporation would be looking to do rights deals so that news, sport and acquired programming can eventually be added to the iPlayer.
At launch next month, the iPlayer broadband TV catch-up service will only offer the BBC's own originated programming - but not news bulletins, because of rights issues.
News will only added when the streaming element of the iPlayer is launched in the autumn, at which point shows such as Newsnight and the BBC4 world news bulletin will be available.
Co-productions such as the BBC/HBO drama Rome will also not be available initially via the iPlayer and nor will most sports programming - although the corporation does have the rights to put its Euro 2008 football championship coverage on the broadband service.
"First generation will see mainly originated programmes by the BBC. The secondary focus is on getting rights for acquisitions. We will gradually work through the issues ... no one is shutting the door," Ms Bennett said.
The BBC director general, Mark Thompson, added that in the future the BBC would make sure it secured download rights to as much TV content as possible.
"In July 1967 colour TV launched as a big milestone in the BBC timeline. This July it is the iPlayer," Mr Thompson said.
"This is at least as big a redefinition of what radio, TV and broadcast can be as colour TV was 40 years ago."
Post-watershed content will be labelled to allow people to make informed choices and there will be the possibility of PIN protection, while under-16s are not, in theory if not practice, meant to register for the iPlayer service.
The BBC director of future media and technology, Ashley Highfield, said he expected the iPlayer to be available via Freeview set-top boxes, once trials of delivery via personal video recorders and a hybrid box with a broadband connection had been successfully completed.
· To contact the MediaGuardian newsdesk email editor@mediatheguardian.com or phone 020 7239 9857. For all other inquiries please call the main Guardian switchboard on 020 7278 2332.
· If you are writing a comment for publication, please mark clearly "for publication".