British MPs have voiced concern about human trafficking and broader criminality in Croatia as it gets set to join the EU.

Deputies spoke out during a debate in parliament on Tuesday (6 November) on British ratification of the Balkan country's EU entry treaty.

Amid broad cross-party support for the move, oposition Labour party and ruling Conservative party MPs said Croatia risks becoming an EU entry point for human traffickers and irregular migrants.

Labour party MP Michael Connarty asked "whether there is a prospect of the mafia - for want of a better word - of the Balkan states using Croatia as a gateway for people trafficking ... Are the police in Croatia up to dealing with such an influx?"

Conservative MP Jacob Rees-Mogg said: "I would highlight Croatia's 2,000 mile border. My concern is not Croatia's 4 million population, but that lots of people can get through a border, as we have seen in Greece ... the extension of the EU has weakened our border controls."

Referring to a recent EU report on shortcomings in Croatia's judiciary and police force, he added that the European Arrest Warrant, a protocol for extraditing criminal suspects, is an extra worry: "Are we really, after the middle of next year, going to allow British subjects to be arrested on the say-so of a Croatian court, when Croatia has a police force in which even the European Commission does not have confidence?"

Labour MP Michael Connarty noted: "Again and again, we are getting strong warning signals that Croatia is not yet in a good place to enter the European Union."

For his part, deputy foreign minister David Liddington defended Croatia's readiness to join.

"We have not identified any victims of trafficking from Croatia in the United Kingdom," he said.

He noted that Zagreb caught almost 1,500 more "illegal migrants" last year than in 2010. He said it convicted 205 people on charges of organised crime between January and August, on top of sentences for corruption of high-level people such as a former PM and a former defence minister.

Liddington added that Croatia is not expected to file an application to join Schengen, the EU's passport-free zone, until 2015, and that the UK will impose limits on Croatian workers who want to come to Britain for "at least" the first two years of its EU membership.

He also indicated the EU could punish Croatia for backsliding after it joins.

"If a member state departs from fundamental standards of human rights and democratic values that are embodied in the articles of the treaty, ultimately its full rights as an EU member can be suspended ... when a far right party entered the Government of Austria a few years ago, Austria found that it started to get frozen out of normal EU business," he said.

With the UK expected to shortly become the 17th EU country to bless Croatia's accession despite the MPs' misgivings, a court ruling in Strasbourg also on Tuesday put the spotlight on a potential Slovenian veto.

The European Court of Human Rights said Ljubljana must compensate two Bosnian citizens who lost their savings in Ljubljanska Banka when the former Yugoslavia broke up.

The ruling is likely to embolden Croatian banks which are suing the now-named Nova Ljubljanska Banka to get their money back.

Slovenia has in the past warned it will not ratify Croatia's accession unless it withdraws permission for the lawsuit to go ahead.