Romania's border controls are a key area of concern for the European Union, as the country gets itself into shape to join the bloc on 1 January 2007.
EU aid has given the border police modern equipment
Failure to raise standards could mean EU entry is delayed, but progress is gradually being made, Anca Toader of the BBC's Romanian Service reports.
When Romania joins the EU it will manage more than 1,500km (931 miles) of the enlarged bloc's external border and Brussels wants to make sure that it will be able to fulfil this role.
"It should be able to prevent the illegal trade in goods and people, without erecting a new iron curtain between the EU and the countries which will be left outside the enlarged Union," explains Jonathan Scheele, the European Commission's chief negotiator in Bucharest.
Neighbouring Serbia, Ukraine and Moldova all have a reputation as transit hubs for smuggled goods and people.
The biggest challenge is posed by Romania's eastern border with Moldova, which is a source of illegal migrants including women trafficked for prostitution to western Europe.
Moldovans can travel without a visa to Romania, which makes it more difficult to differentiate between genuine tourists and potential illegal migrants.
Moldovan guides also take illegal migrants from Africa and Asia across the River Prut that separates the two countries. From there, they try to make their way to western Europe, their final destination.
Romanian border police claim to have made real progress in tackling these illegal activities. Last year they dismantled 30 human trafficking networks, arrested 73 guides and more than 600 illegal migrants.
This success was partly due to a large injection of financial aid from Brussels.
Mr Scheele says that in 2004-2006 the EU allocated 125 million euros (£83m) to modernise Romania's border management.
The programme will continue after accession, until 2009-2010, the earliest date that Romania can hope to join the Schengen area of free movement within the EU.
The impact of Brussels' aid is evident: in the last few years the border police purchased modern equipment, like speedboats, Land Rovers and thermal-imaging cameras.
Bogdan Carp, border police spokesman in Galatzi - one of the counties adjacent to Moldova - says this has dramatically boosted their performance.
"Until recently we used rowing boats to patrol the River Prut," he said. "In fact, we seldom did that anyway."
Now they have speedboats and claim that illegal migration is becoming "less of a phenomenon".
The EU representative in Bucharest acknowledges "Romania's progress in the last five years". But he points out that the reform will be considered finished only when Romania "reaches the standards of old members like Austria and Germany, which for years enforced the 'old' EU's external borders".
Romania must also make sure that its own citizens do not leave the country without valid travel documents.
In 2004, the border police stopped more than 1.5 million Romanians from travelling to the EU, but the filter is not perfect.
Migrants are smuggled across the River Prut from Moldova to Romania
One reason is the corruption among some border police, who accept money in return for turning a blind eye to irregularities in the travel documents of fellow Romanians.
According to the Romanian border police chief, Inspector General Nelu Pop, this is "a particular concern" on Romania's western border with Hungary, one of the new EU members.
Corruption and mere incompetence also led to incidents like one in March this year, when several coaches with more than 200 Romanian citizens on board were refused entry into Spain for lack of valid travel documents.
They crossed Romania's western border to Hungary after having been cleared by the Romanian border police, who were supposed to check that they had valid passports, hotel bookings, return tickets and enough money for their journey.
"Everybody is allowed to make a mistake once," said Mr Scheele. "But it shouldn't happen again, because it would undermine confidence in Romania's ability to control its borders."