The alarm bells at NRL HQ should be ringing loud and clear in the build-up to the State of Origin opener in Sydney.

The fact the game wmay be played in front of thousands of empty seats at ANZ Stadium is nothing short of a disaster for the great game of rugby league.

It's no secret that the country's national competition has been battling to draw crowds for a number of years now, but Origin has typically been the exception.

As Mercury columnist Steve "Blocker" Roach wrote this week, Origin is a whole different beast to your standard game of rugby league.

NRL grand finals and international Test matches will always be great spectacles played in front of large crowds.

But there's a unique atmosphere surrounding the state-versus-state, mate-versus-mate series that can't be matched anywhere.

It can be likened to the Ashes, and maybe to an extent the Wallabies playing the All Blacks.

But even those clashes rarely pit two club teammates against one another. It draws people in who normally couldn't care less about rugby league.

It divides friends, work colleagues, and even family members who claim to barrack for NSW or Queensland.

The passion involved is intense.

Whether you're from NSW, from Queensland, or from any other state in Australia, State of Origin is a highlight of the country's sporting calendar.

But if the NRL fails to sell every last ticket for Wednesday's Origin I, the bigwigs in Sydney might need to take a very hard look at exactly why people are shunning the sport.

More so in Sydney than anywhere else, actually.

The remaining two Origin games in Melbourne and Brisbane are already selling fast and look like being played in front of packed houses at the MCG and Suncorp Stadium.

Yes, that's right, there's a possibility a rugby league game in Melbourne will sell more tickets than a game in Sydney.

There's something wrong with that picture, surely. Victoria has one NRL club - the Melbourne Storm.

It's a state dominated by Australian football.

NSW is supposedly dominated by rugby league.

The boss of Queensland Rugby League, Peter Betros, fired the first interstate missile when he suggested Sydney should lose its right to automatically host an Origin game each year if it fails to sell out game one.

I'm a NSW fan, through and through, but there's some sense in what Betros is saying. Sydney just doesn't seem to draw big crowds to sport any more.

We've seen crowd numbers trending downwards in the state's capital for some time now and nobody has found the solution to remedy the problem.

It was revealed this week that the AFL is the fourth best-attended sporting competition in the world.

Not just in Australia, mind you, but on the entire planet.

It sits only behind the National Football League (American football), the Bundesliga soccer league in Germany and the English Premier League (also soccer).

The average attendance to AFL matches during the home-and-away season in 2014 was 32,436.

The NRL average is in the teens - roughly 16,000.

Supporters of both codes vehemently and constantly claim their sport "is the best in Australia".

If you base this claim purely on crowd figures, the AFL has the NRL over a barrel. But in truth, neither sport is better nor worse than the other.

They are totally different sports. You can choose to follow either.

A lot of people - myself included - follow both with an equal amount of enthusiasm and interest.

So maybe it's the ticket prices?

I could have attended Friday night's game between South Sydney and Parramatta for $25.49, which would have secured me a seat in the general admission area.

For State of Origin it's roughly double that.

I could drive to Melbourne and attend Saturday night's blockbuster between the Hawks and Swans for $25 flat, also in general admission.

So it can't simply be ticket prices, can it?

Has the overall appeal of rugby league dropped so significantly?

I mean, the game is a lot different to 20 years ago, but surely people aren't jumping off the wagon in protest of a few rule changes.

Maybe it's time for the NRL to move away from the 80,000-seat arenas and focus on more traditional venues - Kogarah, Brookvale, Wollongong.

Even get each club to take one of its home games to a regional centre every season.

I know for a fact places like Wagga, Albury, Bathurst, Orange, would all love to host a season-proper fixture.

Whatever the solution, the NRL needs to figure it out quick.