THE Sydney Super Cup involving both Celtic and Rangers may be in serious doubt, according to reports.

It's claimed "unresolved issues with the organiser" are ramping up behind the scenes after the plans for the friendly tournament were announced.

The lucrative November competition will see Rangers and Celtic head Down Under to play each other and A-League sides.

Rangers are due to play Western Sydney Wanderers, Celtic to face off against Sydney FC before the Glasgow derby.

However, now Sky Sports New Zealand broadcaster Jason Pine reports the launch of the event "may have been premature".

Reporting on Twitter, he wrote: "Hearing football’s Sydney Super Cup may be in serious doubt.

"Unresolved issues with organiser escalating behind the scenes according to local sources.

"Launch may have been premature. More to follow."

It comes as Celtic announced tickets for the event would go on sale tomorrow, but fans of both Glasgow clubs remain firmly against the friendly tournament.

Fans of the rival clubs unveiled banners slamming the proposed event after it was announced.

A banner at Celtic Park read: "We're not half of anything.

"*Unless there's money to be made.

"Shove your 'Old Firm' friendly up your a***."

While a display at Ibrox targeting Stewart Robertson read:  “Safe Standing? No. Better Disabled Facilities? No. Friendly Against the Animals? Yes. Shame On You.” 

Another Rangers banner, held aloft in the trip to St Johnstone, read: "Money over morals. No derby friendlies."