Speculation is mounting that Seven West Media will attempt a knockout bid to land AFL and NRL broadcast rights, using its strengthened balance sheet from its large capital raising to target the country's two biggest winter sports.

Seven West, which owns the Seven free-to-air TV network, is in the midst of a $612 million capital raising that sports sources expect frees up Seven to lodge huge bids for AFL and rugby league rights.

It comes as expectations are growing that the NRL will attempt to beat the AFL to the punch and sign a rights deal it hopes will be worth up to $2 billion over five years before the AFL finalises its negotiations for a new contract, which it has told TV networks should be worth about $1.75 billion over five years.

Seven West Media could lob a big bid for rugby league TV rights. Getty Images

The NRL told TV executives at the end of the week before last that it was in the market for a new deal to begin after its current contract with Nine Entertainment Co, Fox Sports Australia and Telstra, worth about $1.2 billion over five years, expires at the end of 2017.

The move came as a surprise, given the AFL has started negotiations for rights that would start after its five-year, $1.25 billion contract with Seven, Foxtel and Telstra ends after the 2016 grand final.