The Ontario Lottery and Gaming Corporation says the 19 Scarborough co-workers celebrating a $50-million jackpot will have to wait a little bit longer for their prize as additional claimants have come forward.

"There has been plenty of media attention on the potential jackpot winners from this draw, but a rigorous prize claim review process needs to be completed before any prize is paid out," OLG said in a statement.

OLG confirmed a Scarborough retailer validated the ticket Monday morning. The ticket was purchased by 19 employees at a Bell Canada call centre who are now planning trips, car purchases and savings plans.

The office pool had only been in existence for four weeks.

OLG media spokesperson Tony Bitonti said at least one other person is claiming that he or she should be on the list of winners. OLG has put a hold on issuing the winnings until the dispute is settled, he added.

"We want to make sure that we pay the right prize to the right person every time," Bitonti said.

It's important that office pools follow the rules and make sure photocopies of the ticket are given to everyone, the tickets are signed and there is a list to document who is in the group and who was paid, OLG says.

Sarah Kiriliuk, another spokesperson for OLG, said it will be the largest-ever prize won by a single ticket in Ontario once it is confirmed.

"There is a very specific prize-claims process that we go through at OLG to make sure we are paying the right price to the right person," she said. "It's really great to see these people excited and to think that 19 people – 19 families – that will be changed when, if, everything goes well."

Group members found out at 2:30 a.m. Monday that they were taking home the $50-million pot -- or about $2.63 million each.

"I scanned it by myself and saw $50 million plus a free ticket," group leader Natalie told CTV News on Monday.

This is the sixth $50-million jackpot issued since Lotto Max was launched in 2009.

Kiriliuk said that this also is the second-largest prize ever won by a group of people of this size in Canadian history.

In 2005, a group of 17 oil and gas workers in Camrose, Alta., won $54 million.

Kiriliuk said large group wins bring with them the risk of complaints from those who think they deserve parts of the prize, whether they are from someone who says they meant to play, or that they had been part of the group in the past.

"Occasionally there are those sorts of problems where somebody says, ‘I was supposed to be part of this group,' but in this case I get a good sense that everything was very organized and they knew who was in the group and who wasn't," Kiriliuk said.

"There are a lot of people in the group, so it will take a lot longer to process this than if it was one winner."

When OLG starts the prize claims process, they have the group leader fill out a group claim form that must be signed by everyone involved. This ensures that everyone understands who is included in the group list when they sit down with officials.

The 19 winners have booked off the rest of the week while they sort out the dispute. Each will be interviewed by OLG officials before the winnings are awarded, Bitonti said.

With a report from CV Toronto's Tom Hayes