Fans selling tickets through unauthorised secondary sites could be hit with an indefinite ban from Anfield, Liverpool have announced.

The issue of ticket availability is a long-running one for Reds supporters – even taking into account the recent Main Stand expansion which has extended the capacity to over 54,000.

Having received just 16,613 tickets for next month's Champions League final against Tottenham in Madrid a club ballot for supporters not guaranteed a ticket via previous attendance criteria received 30,508 applications, Press Association Sport understands.

Fans had just a one in four chance of being successful and within hours of the results being announced there were reports of tickets being resold for several times their face value.

On Friday morning one resale site had tickets ranging from £2,800 to £35,000.

It prompted Liverpool, who have had a ticket investigations team operating for 18 months, to issue advice to fans considering buying these tickets and a warning to others who were reselling them.

"Fans are warned that buying tickets via unofficial online sources does not guarantee tickets are genuine or that they will actually receive them," said a club statement.

"As part of its commitment to tackle ticket touting, the club has created a test purchase programme to help protect supporters from purchasing via unauthorised ticketing sites. The programme aims to identify and stop these sales.

"While selling or offering to sell tickets without the permission of the club is a criminal offence, LFC also intends to impose sanctions on any supporters found to be selling tickets through unofficial secondary ticketing sites.

"Sanctions could include ticket-buying suspensions and indefinite bans from Anfield.

"It could also mean that any tickets for the Champions League final in Madrid are invalid, and purchasers will be unable to gain access to Estadio Metropolitano."