The Republic of Ireland's World Cup qualifier clash against Portugal next month is a complete sell-out with the Aviva Stadium set to host over 51,000 soccer fans for the first time in two years.

However, the FAI has acknowledged that match tickets are currently circulating online at inflated prices and warned that fans who purchase tickets via this manner risk being denied entry.

"The FAI would like to thank all of those fans who have bought tickets for the upcoming FIFA World Cup 2022 fixture against Portugal at the Aviva Stadium which is a sell-out," a statement from the association read.

"We are aware however that tickets for the match are being offered at inflated prices online and we remind fans who purchase tickets from a third-party website or any unauthorised seller that they risk not receiving a ticket at all or being denied entry with an invalid ticket."

The last time the Lansdowne Road venue had a full house was back in November 2019 when a 1-1 draw with Denmark ended Ireland's hopes of qualifying automatically for the Euros. Instead they headed for the play-off semi-finals, where they were beaten on penalties by Slovakia.

Stephen Kenny's side cannot even make the play-offs in this campaign but an upswing in results has created momentum around his team.

Earlier this month a 3-0 win in Azerbaijan - Kenny's first competitive victory - was followed up by an impressive 4-0 dismantling of Qatar in a friendly. That game was played in front of over 25,000 supporters, the permitted capacity limit at the time.

Ireland are currently fourth in a five-team Group A with two games to go - they travel to Luxembourg in their final match - but tickets were quickly snapped up after going on general sale at 10am this morning.

Sporting venues are again allowed to operate at 100% capacity under the Government's revised reopening plan, which was published last Friday afternoon.

The FAI Cup final between Bohemians and St Patricks Athletic takes place on 28 November at the Aviva and could have the largest attendance since the first Aviva Stadium final back in 2010, when 36,000 saw Sligo Rovers beat Shamrock Rovers on penalties.