Norway's trillion-dollar sovereign wealth fund plans to dump oil and gas companies from its benchmark index, the finance ministry announced on Friday.

The move, initiated by Norges Bank which manages the fund, is designed to make the Norwegian government's wealth less exposed to a lasting drop in oil prices.

"The Government is proposing to exclude companies classified as exploration and production companies within the energy sector from the Government Pension Fund Global to reduce the aggregate oil price risk in the Norwegian economy," the finance ministry said in a statement published on its website.

The exclusion will affect companies that explore and produce oil and will not impact integrated oil and gas companies such as BP and Shell. The Norwegian government also said that the companies to be excluded are those belonging to FTSE Russel's Index sub sector called exploration and production. According to the government, the value of 134 stocks to be excluded from fund amounted to NOK 70 billion ($7.9 billion), Reuters reported.

Shortly after the announcement, energy stocks worldwide extended losses on Friday morning.

International benchmark Brent crude traded at around $65.18 on Friday, down around 1.7 percent, while U.S. West Texas Intermediate (WTI) stood at around $55.78, more than 1.6 percent lower.

Energy stocks are notoriously volatile. Brent crude collapsed from a near four-year high of $86.29 in early October down to $50.47 in late December — marking a fall of more than 40 percent in less than three months.