TELEVISION'S two fiercest rivals - the Seven and Nine networks - have discussed an unprecedented deal to share coverage of Australia's two biggest football codes.

Under the proposal, Seven would show at least one NRL game live in NSW and Queensland, while Nine would broadcast an AFL match in the southern states.

The move, which would quash any hopes by the Ten network of gaining a ratings foothold in either code, comes amid manoeuvring for the upcoming league broadcast rights which are expected to reap more than $1 billion for the NRL.

''It's definitely on the table,'' said a source close to the discussions. ''It's been discussed and there's a real chance it could happen.''

It is believed the Nine-Seven discussion about the potential sharing of AFL and NRL games was first raised several months ago.

A Seven-Nine free-to-air trade would allow pay TV's Fox Sports the flexibility to simulcast all rugby league matches as it presently does with AFL matches, further adding value to any future rights package.

The chief executive of the NRL, David Gallop, said he was unaware of the Nine-Seven talks but was not surprised that such an unprecedented option was being considered.

''We're at a stage where there's no doubt there is a lot of talk going on behind the scenes,'' Mr Gallop said.

''While not privy to all discussions, it does underline the interest out there in all of our products.''

The NRL held initial talks with Ten and Seven last month after current rights holders Nine and Fox Sports submitted their first formal bids. A joint bid by both is expected in the next two months, with the League hoping to reach an agreement by September.

The Australian Rugby League Commission has joined forces with corporate advisers Greenhill Caliburn to negotiate the new rights package. Industry analysts have valued the rugby league five-year package at $950 million but league sources say they may consider extending any deal by another year to capitalise on the current market interest.

A key aspect of the negotiations will revolve around State of Origin matches and the potential of Fox Sports to set up a dedicated rugby league channel along the lines of its AFL version.

The NRL was buoyed last month by the record television audience for this year's first State of Origin, in which an average nationwide audience of 2.51 million watched Queensland defeat NSW at Melbourne's Etihad Stadium.

Last year Seven, Foxtel and Telstra paid a record $1.25 billion over five years for the AFL broadcast rights, a rise of more than $400 million on the previous deal and underscoring Australian football's status as the nation's richest code.

Industry analysts believe Seven and its partners ultimately paid too much for the AFL package, but the main free-to-air networks and Foxtel are content to view them as ''loss leaders'' and key audience drivers.

Ten has signalled a strong interest in bidding for the NRL rights.