The rally has drawn interest from militias and extremist groups across the country, raising security concerns in Richmond.
Northam (D) has announced plans for an afternoon news conference on Wednesday. His office did not respond to questions seeking comment on the ban, which was first reported by the Associated Press.
Security has been unusually tight during the General Assembly session that kicked off last week, as Democrats — who won control of the House of Delegates and state Senate in elections in November — consider far-reaching gun-control legislation.
State Police have been out in force, providing backup for the Capitol Police, who normally patrol the square. Crews have been erecting steel crowd-control barricades around the manicured Capitol grounds in recent days.
The teenagers who normally work in the House and Senate as pages were given the day off Monday, the first business day after a joint House-Senate committee on Friday banned weapons from the Capitol and legislative office building. The ban is not subject to review by the full legislature.
Hundreds of gun rights activists flocked to the Capitol that day to protest the ban and to testify against the first gun-control bills to make it to a Senate committee that morning.
The Senate Judiciary Committee advanced four bills to the full Senate. The measures would require background checks on all firearms purchases, allow law enforcement to temporarily remove guns from individuals deemed a risk to themselves or others, let localities ban weapons from certain events and government buildings, and cap handgun purchases at one per month.
There were no incidents Monday, but law enforcement officials remain concerned about the rally planned for next week. That event is being organized by the Virginia Citizens Defense League, one of many grass-roots groups that turn out every Jan. 20 — Martin Luther King Jr. Day — for what is a traditional day of citizen lobbying at the state Capitol.
This year, VCDL expects a much larger crowd because of the sweeping changes to gun laws that Democratshave promised to usher in. Democrats won their majorities in the November elections, ending a 26-year stretch when Republicans were able to quash any proposed restrictions on guns.
Gun control took on greater prominence in the fall elections following a deadly mass shooting in a Virginia Beach in May and after the GOP-controlled legislature swiftly adjourned a special session that Northam had called in the aftermath.