A new round of talks in Moldova's simmering dispute with the pro-Russian breakaway region of Transdniestr, a sliver of land bordering Ukraine, is expected to take place in May, an official has said.

"We are very much expecting the next round to take place in May", said Jennifer Brush, the head of mission in Moldova for the Organization for Security and Cooperation in Europe.

The seven parties involved "are all interested in having these talks continue", though the current tensions in Ukraine bring an amount of uncertainty, Brush said.

A round of talks planned in April was postponed because of a dispute over an excise tax law that has since been withdrawn by Moldova.

Talks to broker the Transdniestr "frozen conflict" resumed in 2011 in what is called the "5+2" format - including Moldova, Transdniestr, Russia, Ukraine and the OSCE, with the European Union and the United States as observers.

Mainly Russian-speaking Transdniestr made its bid for secession in 1990 as the Soviet Union crumbled, fearing domination by the Romanian-speaking population that makes up the majority in Moldova.

AFP