
The report noted that many shoppers still go ahead with their purchase, costing them up to £100m per annum extra as a result.
Some 47 percent of flight bookings had a final 'check-out' price higher than the initial price. For these, the median price increase was 19 per cent, but many increases were much more.
The report said that these charges annoy shoppers, a point echoed in a recent survey commissioned by MoreComputers.com.
This report found hidden delivery charges to be the most annoying, with 64 percent saying it puts them completely off buying from the site.
"The report reiterates the strength of feeling we found in our survey. Internet shoppers have had enough and are crying out for something to be done about philfing," said Brian Trevaskiss, operations manager at MoreComputers.com.
"The OFT said that there could be scope to extend advertising self-regulation and that it is going to explore with the Committee of Advertising Practice whether its remit could be extended to cover websites. We will strongly encourage this move to level the playing field."