Fadel Salman Matrouk was shot on Tuesday at the funeral of Msheymah Ali, who died earlier in the day from wounds sustained during Monday's day of protests.
The Islamic National Accord Association, which has 18 seats in the 40-member house, has "suspended its membership in the Bahraini parliament”, MP Khalil al-Marzooq told the AFP news agency.
The interior ministry has promised to investigate both deaths.
Matrouk was killed when "some of the people participating in the funeral on Tuesday clashed with forces from a security patrol", it said.
It also promised an inquiry into whether there was "unjustified use of arms" at the demonstration in Diya village, where Ali was wounded on Monday.
Thousands attended his funeral and activists are appealing for a big turnout when Matrouk is buried, as well as further protests.
The Facebook page calling for a "day of revolution" on 14 February calls for Bahrainis to unite across the religious divide to win change.
A wave of protest in the 1990s died down after parliament was restored in 2001.
But the Shia-based opposition opposes the existence of an appointed upper house of parliament and accuses the regime of trying to change the nation’s demographic by naturalising Sunni immigrants.