Ryanair is warning Facebook users about an online scam giving away free tickets in honour of the company's 35th anniversay.

The budget airline posted on Twitter today saying the 'offer' was not all it seemed on the surface.

A Facebook post claims there is an offer to "Get 2 Free Tickets on its 35th Anniversay!"

But eagle-eyed users spotted the image posted with it wasn't genuine, reports the Irish Mirror.

The first clue was that the ticket had a Qantas flight number.

Secondly, the seat number quoted - 4K - doesn't exist on Ryanair flights. The airline flies narrowbody Boeing 737 aircraft, in a 3-3 configuration, with seats A,B,C, and D,E,F. 4K would seat passengers on the wing.

There also appears to be frequent flyer details on the picture.

One Facebook user said: "I did not know that Ryanair changed the IATA code to QF and also joined OneWorld. Good to know!"

Another said: "So seat K would be on the wing then????"

Another added: "Plus this wasn't your 35th anniversary but your 31st!"

The firm said in its posts: "Please be aware of an online scam offering free Ryanair tickets. This is not an official promotion."

It follows a similar scam that affected rival airline Aer Lingus earlier this month.

Aer Lingus posted about a supposed offer on August 10 and said: "We're aware of an online scam offering free Aer Lingus tickets.

"This is NOT an official Aer Lingus promotion.

"For your own information security, please don't click on any posts in your Newsfeed similar to this one."

In a similar style to the Ryanair image, that image supposedly two free tickets for Aer Lingus' '80th anniversary'.

The previous link had led to a questionnaire that asks users to share it with 15 of their mates before texting a number for €2 to claim the flights.

Ray Shah posted about the scam earlier this month and said: "To all those who were gullible enough to have shared this or think a company is going to give away a car... use a bit of cop on."