Elections BC says 37 per cent of voting packages in British Columbia's electoral reform referendum have been returned and 31 per cent of them have been screened a week before ballots must be received.

The deadline for getting the mail-in packages was extended to next Friday, with an extra seven days added due to rotating strikes at Canada Post.

Elections BC says the highest number of returns at just over 46 per cent came from the Vancouver Island riding of Parksville-Qualicum, a jump from 29 per cent a week ago.

Surrey-Green Timbers had the lowest returns at 17.8 per cent, up from 9.7 per cent last week.

Voters must decide whether they want to keep the current first-past-the-post system or change to a form of proportional representation for the next election in May 2021.

Any move away from the current system would require a vote of 50 per cent plus one in favour.