Puppies bought during lockdown could be abandoned once restrictions are eased, rescue workers fear.
Internet searches for "buy a puppy" increased by 120% during the first month of coronavirus restrictions, according to the Dogs Trust.
Now staff at a Carmarthenshire shelter have urged people not to buy a puppy during lockdown.
Owner of Many Tears Rescue Centre, Sylvia Vanatta, said new owners may be unable to commit once back in work.
"Bringing a puppy up is hard work even when we're not in lockdown, making sure it turns out socialised and balanced needs work," she said.
"You can't go to dog training club or even to the vet. You won't realise you've got a problem until it's maybe nine months old and then it could be a big problem."
One-year-old jackapoo Leo arrived at the Many Tears centre in Cefneithin four months ago, after he was almost put down because his owner was unable to cope.
A vet in Swansea contacted the centre saying Leo was showing signs of aggression and his owner was struggling.
Ms Vanatta said Leo was an example of how a dog can pick up bad habits from not being socialised properly from a young age.
Like many charities and rescue centres, the centre is struggling with the financial cost of coronavirus restrictions.
About a third of the 52 staff employed at the centre have been furloughed and, while fundraising events have been cancelled, the dogs still need to be fed and bills paid.
But Ms Vanatta fears the centre will struggle to cope as more owners realise they cannot commit once they go back to the office.
While potential owners are currently unable to visit the centre to pick out a new pet, they are being put in touch online, with their homes vetted virtually by staff.
Karen Jones, from Penclawdd, adopted Archie after a successful virtual home inspection and vetting to make sure her home was suitable for the Cavachon.
Ms Jones, who has adopted from the centre before, said it "meant everything to be able to do this".
"If it wasn't for centres like this, I hate to think what would happen to these dogs," she said.
"They deserve a happy life full of love."
Prices for some pedigree breeds have soared online during lockdown, which the shelter said may be a sign that now might not be the best time to make the commitment.
A quick search online across local sites showed one cocker spaniel puppy on sale for £2,200 - about twice its normal price.
One of the UK's largest welfare charities, the Dogs Trust, has changed its 30-year "a dog is not just for Christmas" slogan, in a bid to get people to think twice about getting a pet during lockdown.
Angela Wetherall, rehoming manager at its centre in Bridgend, said it was vital people thought carefully about the commitment involved.
"A dog is for life, and in this case, not just for lockdown, so we want people to really think about the long-term commitments of having a dog," she said.
"We are really concerned that we may see a spike as we do at Christmas of people wanting to give up their dogs when reality sets in. So it's really important people are thinking longer term."
The charity has released a checklist for people thinking of getting a puppy.
It includes: giving up lie-ins; spending more time at home (after lockdown) or paying for a dog sitter or walker; going for walks in snow, rain and gales; paying for food, insurance and vet bills; and picking up after your pet.
But if you have already made the commitment during lockdown, Ms Vanatta has these words of advice: "Just make sure that when things end, you're going to be there for that puppy."