The rising level of the St. John River has prompted the New Brunswick legislative assembly to adjourn early.

Sandbags surrounded the legislature on Wednesday as the overflowing river crept closer to the building, which sits in downtown Fredericton between Queen and King streets.

Projections from the province's Emergency Measures Organization indicate the river could reach 8.6 metres by Thursday morning, which could flood the legislature building.

New Brunswick's elected representatives will be heading back to their ridings on Wednesday evening. If the flood waters reach the legislature building, power will be shut down.

NB Power is warning residents and businesses in the downtown area of the capital that power could be turned off as early as Thursday and would be out for several days.

Speaker Roy Boudreau said if the flooding causes long-term damage, the legislature may reconvene on higher ground in the city at a hotel boardroom or at one of the city's universities.

"If we don't have any water and no damage, great," Boudreau said. "But if there is sufficient or heavy damage then we won't have any choice but to find an alternative site."

The legislature is scheduled to resume on May 13.

Employees were in the basement of the building on Wednesday assembling boxes with documents and records to move to another location.

Among the documents being moved were old newspapers and atlases from the 1800s. The copies may be the last of the documents still in existence in the provinces, said legislative librarian Kenda Clark-Gorey.

"Other places, when they clean out, they send that material to us, so there are some items that would be very, very hard to replace, if they're replaceable at all," Clark-Gorey said.