Elections BC is urging British Columbians who haven't yet voted on the upcoming referendum on electoral reform to mail in their ballots this week to make sure they arrive in time.

The deadline for Elections BC to receive the ballots is Nov. 30 at 4:30 p.m. PT, but rotating strikes by Canada Post have affected delivery times.

"At this point, it's unclear what the situation will be at the deadlines," said Rebecca Penz, spokesperson for Elections BC.

"We are, right now, just monitoring the situation with Canada Post."

The chief electoral officer has the authority to extend the voting period if necessary, should the strikes affect voters' ability to return the ballots before the deadline.

"If [voters] have already mailed their package or if it gets mailed in a timely fashion now, their package will count," Penz told Stephen Quinn, host of CBC's The Early Edition.

Ballots can also be submitted in person at Service B.C. offices around the province or a Referendum Service Office.

Locations in the Lower Mainland include Brentwood Town Centre in Burnaby, Eagle Ridge Plaza in Coquitlam, Lansdowne Centre in Richmond, Guildford Commerce Court in Surrey, and Chinatown Plaza and Oakridge Plaza in Vancouver.

Canada Post workers have been on rotating strikes for the past month and some are concerned about the impact on B.C. voters' ability to mail in their ballots. (Andrew Vaughan/Canadian Press)

No minimum turnout required

As of Friday morning, Elections B.C. had received ballots from 18 per cent of eligible voters. More came in over the weekend but numbers haven't yet been confirmed.

The campaign urging British Columbians to vote against proportional representation has already called for the voting period to be extended due to the strikes and poor voter response.

There is no minimum threshold for voter turnout in any referendum but previous referendums in B.C., like those on the electoral system in 2005 and 2009 or on the harmonized sale tax in 2011, all had a voter turnout of more than 50 per cent.

"Establishing minimum turnout would be up to government," Penz said. "Election BC's role is to make people aware of the referendum and make it as accessible as possible."

Voters who haven't received a ballot can still apply for one in person, online or by phone. The deadline to request a ballot is Friday, Nov. 23, at midnight.

With files from The Early Edition