BUCHAREST, Oct 13 (Reuters) - Joining Europe's open-borders Schengen area would add half a percentage point to Romania's annual economic growth as well as bolster investment and confidence, Finance Minister Adrian Caciu said on Thursday.

European Union governments are expected to vote in December on whether to admit Romania, its southern neighbour Bulgaria and also Croatia, a decision which requires unanimity.

"The boost would come from exports, new investment and commercial flows," Caciu told reporters.

A previous vote held in 2011 was blocked by several states citing concerns about corruption and organized crime. Romania and Bulgaria are on major illegal trade routes to Europe for arms, drugs and human trafficking.

In August, German Chancellor Olaf Scholz said Romania, Bulgaria and Croatia all met the requirements to become full members of the bloc's passport-free Schengen area, which also includes several non-EU states such as Norway and Switzerland.

Romanian President Klaus Iohannis said on Wednesday during an official visit by Dutch Prime Minister Mark Rutte that Romanians had a "legitimate expectation" to join Schengen.

"Romania fulfills the technical requirements for membership and is already acting as a de facto member towards protecting the EU and its external borders," Iohannis said.

"We hope the political requirements will be met as soon as possible in a European context where consolidating resilience and ... solidarity are extremely important." (Reporting by Luiza Ilie Editing by Gareth Jones)