GENEVA (AP) -- The Swiss Cabinet's office says the nationalist Swiss People's Party has gathered enough signatures to force a referendum on banning the central bank from selling any gold reserves.

The Federal Chancellery in the capital, Bern, said Thursday that the initiative known as "Save Our Swiss Gold" had gained more than the required 100,000 signatures to force a vote among Swiss citizens within the next few years.

The party began pushing for a referendum, a mainstay of Swiss direct democracy, more than two years ago. It would require the Swiss National Bank to keep at least 20 percent of its assets in gold.

As of the start of 2013, just over 10 percent of the central bank's nearly 500 billion Swiss francs ($537 billion) in assets were gold.