Nepalese citizens are preparing to vote for an assembly that will rewrite the country's constitution and decide on its political future.

European Union election observers have been touring Nepal and meeting with local election officials in the run up to the historic vote, which will take place on next Thursday.

The team visited Biratnagar, a city about 400 kilometres east of the capital Katmandu on Saturday to review poll security and other arrangements for the election process.

The EU delegation, made up of observers from 22 different EU countries as well as Norway and Switzerland, is the largest international election observation mission in Nepal.

Jan Mulder, the chief EU election observer, says the delegation makes it their point that they will be impartial and neutral.

"We are here to observe, not to interfere in the elections. We will report as honestly and objectively as possible. We might be critical but in the end we hope to be constructive as well."

The EU observers are expected to give their preliminary assessment of the election at a news conference next Saturday.

They are also expected to stay in Nepal for several weeks after the election to observe the ballot counting. The mission will then publish a more comprehensive, final report in June.