Switzerland's parliament has rubberstamped a controversial plan to buy six unarmed Israeli surveillance drones worth CHF250 million ($256 million).

On Monday, the Senate voted for the purchase of six unarmed Hermes 900 drones (30 votes for, 12 against), which followed earlier approval by the House of Representatives.

Campaigners had criticised the deal with Israeli company Elbit Systems, urging Switzerland not to invest in Israel's military complex due to its "systematic human rights abuses" against Palestinians.

Speaking on behalf of the minority that opposed the deal, Social Democrat parliamentarian Geraldine Savary accused Israel of using the Hermes 900 during the 2014 Gaza war, in which 2,251 Palestinians and 73 Israelis were killed.

In his attack, Greens parliamentarian Luc Recordon said: "Israel does not respect the rights of the population, and sometimes uses extremely violent means."

Swiss Defence Minister Ueli Maurer defended the purchase, arguing that Switzerland was not buying the drones from the state of Israel but from a private company, and that they would be used only for surveillance by Swiss border guards.

"We have no intention of arming them," Maurer said.

Centre-right Christian Democrat senator Isidor Baumann said the border guards needed the new replacement drones to replace the current aging models. He said the new ones “meet all the best quality criteria for a good price” to ensure aerial surveillance.

Maurer also insisted that while neutral Switzerland is barred from selling military equipment to any country at war, including Israel, the same rule does not apply to imports.

"There is no problem from a human rights perspective," he said.

The 2015 armament budget stands at CHF1.4 billion, up from CHF771 million in 2014.  

In compliance with the JTI standards

More: SWI swissinfo.ch certified by the Journalism Trust Initiative