The Twenty20 Big Bash League will be shown on free-to-air television for the first time under the terms of cricket's new A$400 million broadcast rights deal.

The second edition of the city-based tournament begins in Melbourne tonight, with the Sydney derby between the Sixers and the Thunder to follow at the SCG on Saturday night.

The competition is now televised by Fox Sports but under the new broadcast rights arrangement with Cricket Australia, to be finalised in the new year, Channel Nine will also get a slice of the local T20 pie. Fox Sports has agreed to allow Nine to simulcast the BBL finals - two semi-finals and the final itself - as part of their bid to retain the domestic rights, which expire at the end of the season.

There have been suggestions that the overall new cricket rights package will fetch as much as A$500 million over five years. CA estimates its total television deal revenue will top A$1 billion, taking into account its overseas contracts such as its rich deal with India's ESPN Star Sports.

However, sources close to the negotiations have told Fairfax Media the most the rights would draw would be A$80 million a year, making a total of A$400 million over the five-year term.

There are hopes the BBL and domestic one-day component, which Fox Sports now pays A$12.5 million a year to broadcast - will rise to as much as A$30 million a year. Sources claim that figure is also optimistic, saying the real value of the domestic limited-overs competitions, driven mainly by a successful BBL, would be between A$20 million and A$25 million.

Negotiations between the existing television companies and CA have crept along slowly and are certain to continue into the open market beyond Nine and Fox Sports' period of exclusivity, which ends on December 31. There is expected to be competition from Seven West Media and Network Ten, but they are constrained by, respectively, Australian Open tennis commitments in January and financial problems.

The loose alliance formed by Nine and Fox Sports is similar to the way the pair worked to retain the A$1.025 billion rugby league rights in August. While that was effectively a joint bid, the two are not formally aligned in their discussions with CA over cricket but their agreement over the BBL finals demonstrates they are working in tandem to ensure they keep the rights.

It has been reported that Nine would, in return for Nine simulcasting the BBL finals, hand off some midweek one-day internationals in the summer not featuring Australia. However, it is understood Nine has made it clear it will not give up any of its ODI matches.

Nine, which has held the rights for more than three decades, has first and last rights for the new deal and will be desperate to retain them. The previous seven-year arrangement, signed off by the late Kerry Packer, was for A$315 million over seven years.

Nine has been keen to capture a slice of the BBL, allowing it to take on Seven and its tennis coverage head-on in combination with limited-overs internationals, but has baulked at taking any more than the three finals, concerned at overloading the schedule due to the restrictions of the advertising market.

The first version of the revamped BBL was a hit. Average crowds of 18,000 were a boon for CA and the competition was a key tool in luring new subscribers to Fox Sports.

Ratings were also eye-catching. The tournament delivered an average audience of 282,000 in 2011-12.

- Sydney Morning Herald