TV3 is laughing all the way to the bank by broadcasting the phenomenally successful X Factor, with advertisers forking out a premium of more than 20% to feature during breaks.

Sources say advertisers cannot get ad slots during the primetime Saturday night schedule featuring The X Factor because of the high demand, which means that TV3 has been able to hike its prices to around €18,500 for one 30-second ad.

Advertising sources say the package is "approximately 20% higher than what advertisers would usually pay but is a very fair price given that it is one of the biggest ad slots of the year with some of the biggest hype surrounding it".

The figure is significantly less than the £200,000 that advertisers in Britain are expected to pay for a 30-second slot on ITV for the final programme.

Another media buyer who has availed of the TV3 package said the station stood to profit massively from a bumper Christmas ad programme.

"The station will not only pull in a massive amount of viewers but they will improve an already successful year with ad revenue from programmes like The X Factor. The show is a talking point and the station will benefit hugely. Combine this with the fact that voting lines were opened for the show and with the hype surrounding Mary Byrne and it is an advertiser's ideal time, right there at Christmas," said the source.

A spokeswoman for TV3 declined to comment on the demand for the slots during the show, saying: "TV3 does not comment on commercially sensitive information such as this".

The show has been a ratings winner for TV3 this year, attracting up to 750,000 viewers on Saturday and Sunday nights; it accounted for 28% of the station's audience last month.