EU:European Commission vice-president Margot Wallstrom has warned there is a danger of a two-speed EU emerging if there is no deal on amending the EU constitution.
She has also accused some EU leaders of promoting referendums on a new EU institutional package as a way of boosting their own popularity.
"A lot of people would like to use the referendums as a tool for their own purposes because they are proposing referendums hoping for a 'No'," Ms Wallstrom told The Irish Times in an interview to celebrate the EU's 50th birthday.
"They think this would be a way to get a more friendly response if they promise a referendum and describe it as the most democratic tool, which is not necessarily true People are saying we pay for these politicians and if they can't take a decision on these things then why should we have them. Why not vote on everything?"
Ireland is probably the only member state which must under its own constitution hold a referendum on EU treaties but Eurosceptic politicians in several EU states such as Poland and the Czech Republic are pressing hard to hold a vote on any new treaty.
"It is really up to member states according to their own democratic traditions to decide, and in some countries it is necessary, but in others it is used as a political instrument," said Ms Wallstrom, who said referendums were often not the best way to ratify EU treaties due to their complexity.
"The problem in all this is the European aspect is missing. There is a need to create a European public sphere and at least some co-ordination where the people can get the feeling that they are in a discussion about Europe," says Ms Wallstrom.
She suggests that a week could be put aside to discuss the institutional issues publicly before either parliamentary votes or referendums are held in all 27 EU member states. Ms Wallstrom, who stands in for Commission president José Manuel Barroso when he is away from Brussels, manages institutional relations and communications policy at the commission.
A former minister for social affairs and culture in Sweden, she was a strong advocate for the EU constitution, which Dutch and French voters rejected in referendums in mid-2005, prompting a crisis of confidence among pro-Europeans.
Ms Wallstrom now concedes there will have to be changes to the treaty due to opposition from states such as Poland, the Czech Republic, Britain and France.
"The ambition or hope is that we can keep as much as possible of the negotiated package but there will also be some things that are new and added to the text," she says. The name will probably have to change and new challenges such as climate change and energy will have to be mentioned in any new EU treaty.
Aware of the danger that states will be unable to agree a new treaty to streamline EU decision-making, Ms Wallstrom says this would not be a "disaster" but it would create risks for the union's future cohesion.
"It would be like an extra large body trying to squeeze into small clothes. We would be unable to tackle the problems that we expect politicians to deal with, so it would be very counterproductive," she says.
"The risk is that you get a two-speed or several-speed Europe with some member states wanting to take initiatives in the field."
This scenario, sometimes known as "variable geometry", would enable some states to go ahead with closer integration in groups. It has already occurred with the euro and Schengen, an agreement to remove national border controls. But critics fear this could undermine EU cohesion.
"For decision making and democratic functioning of the EU you cannot apply different rules. In the way we act towards the rest of the world we also have to have someone who works effectively at representing the union," says Ms Wallstrom, who adds that Europe is not predestined to go in the direction of closer integration.
"I don't think we should pretend that it will always be the same and there is one way to go with the EU. "We decide how it goes and until now it has been like dancing the tango, with two steps forward and then one back. It takes two to tango and it takes member states and the EU institutions to agree on where to go and where to dance."
As well as taking care of institutional issues, Ms Wallstrom is also charged with helping the EU communicate with citizens, and in the process boost its flagging popularity.
Polls show just over 50 per cent of the public think the EU is a positive thing, so the Swedish commissioner clearly has her work cut out.
So why is the EU so unloved in many member states? "Very often it is depicted as too big or too powerful and therefore a threat or on the other hand it is seen as interfering, with rules such as regulating the content of sausages, and then ridiculed," says Ms Wallstrom.
"It is very rare that we get a realistic impression of what the EU does, even though we are engaged in many positive activities such as preserving cod stocks in the North Sea or tackling famine in Africa."
She also points out that "EU-bashing" among national politicians is still in vogue in many states and the public shows little trust in national political institutions either.
In an attempt to woo a Eurosceptic public, Ms Wallstrom has launched several initiatives aimed at getting national parliaments and civil society more involved in EU business. She started the first online blog by a commissioner, and is promoting a citizens' agenda called Plan D (for democracy).
"This is not something you achieve in one week or even one year. From the beginning I realised I would not even be able to say that I had achieved everything in my mandate. But if I could put things on the right track I'd be happy."