The world’s biggest games retailer GameStop is preparing to launch an online assault on the UK market in time for Christmas.

The plan to launch its UK website in November will concern rivals that have long worried about when the games giant will make its next move in the competitive UK market.

GameStop, which clocked up sales of $9.08bn (£5.9bn) in 2009, operates just two stores on the UK mainland, in Birmingham’s Bull Ring and in Stockport. Both opened in 2005.

Gamestop.co.uk, which will be backed by a marketing push, will go head-to-head with rivals including market leader Game, HMV, supermarkets and pure-play etailers Amazon and Play.com.

The US retailer, which has 6,500 stores across 18 countries, has no web presence in the UK currently. It operates a non-transactional website in Ireland, which will be relaunched as a transactional site, Gamestop.ie, later this month.

GameStop is the biggest games retailer in Ireland, operating 50 stores in Ireland and five in Northern Ireland.

GameStop declined to comment, but one source close to the situation told Retail Week the move showed the retailer is “keen on the UK”. “It’s still the biggest games market in Europe”, the source added.

The retailer would not comment on future UK store openings, but it is known that GameStop has been wanting to open stores in the UK for some time, and is regularly linked to a takeover of market leader Game, which has 1,300 stores globally, including 444 in the UK.

The launch comes at a time when games retailers have been suffering declining sales in what is a highly cyclical market. Game’s like-for-likes slumped 17.2% in the 19 weeks to June 12.

Numis analyst Andy Wade said the “low risk, low cost” strategy makes sense for GameStop, which is “not a massive brand over here”.

He added that the move does not necessarily indicate an imminent roll out of stores across the UK but warned: “It can’t be a positive for Game. It’s another competitor in an already competitive space.”