The organisers of the Web Summit have said negotiations are continuing with a number of European cities about the possibility of moving the tech conference out of Ireland next year.

It is understood the talks are taking place with city authorities in Lisbon and Amsterdam, as well as with agencies in Dublin about the future location of the event.

Paddy Cosgrave, co-founder and CEO of the event, said as negotiations are ongoing he could not discuss the details, for fear of prejudicing the outcome.

But he added that irrespective of whether Web Summit takes place here or not in the future, Dublin will always be its home.

He was speaking at an event to launch Web Summit 2015, which take place at the RDS in Dublin between November 3-5.

This year's event will see the number of attendees grow from 22,500 last year to an expected 30,000, with the number of individual summits taking place rising to 21.

As well as the return of the sport, enterprise and machine stages, there will also be new summits focused on areas like fashion and health tech.

Big name speakers already confirmed for the event include Sean Rad from dating app Tinder, Da Vinci Code author Dan Brown, Instagram founder Mike Krieger and Tour de France winner Chris Froome.

Mr Cosgrave said Web Summit is now the largest and most important startup gathering in the world.

The event began in 2010, when it had 400 attendees, and has quickly mushroomed.

The company behind it, Ci, now employs 130 people and also runs similar events in the US and Asia.

Mr Cosgrave said in the five years since it started, the 3,000 startups that have attended have raised a total of €1.2 billion in funding.

Other events taking place around this year's Web Summit include a speed dating event for startups and investors, an Angel Summit for early stage investors, and Accelerator Summit for people running business accelerator programmes and a Startup University.

Mr Cosgrave said negotiations are ongoing with the RDS over wifi coverage. During last year's event Mr Cosgrave publicly apologised to delegates on a number of occasions and criticised the RDS over the poor wifi service.

This year for the first time registration for delegates will be available at Dublin airport.