Sir Keir Starmer has described Conservative Party claims that Labour's plans on immigration would increase asylum seeker numbers as "nonsense".
Speaking exclusively to Sunday Morning with Trevor Phillips, from a summit in Montreal, the Labour leader maintained the government has "no control" of UK borders.
He said: "What concerns people is that basic idea that the government ought to control who comes to this country and now it's the gangs that decide who should come to the UK.
"What I'm focusing on is how we're actually going to deal with this."
Labour has already said it will consider accepting an EU migrant quota as part of a returns agreement - if it gets into power.
The new returns agreement currently being worked on by the EU would mean each member state takes a minimum annual quota of 30,000 migrants, or pays €20,000 (£17,200) for each person they do not accept.
But Sir Keir clarified: "Let me be absolutely crystal clear about this, because the government has been pumping out complete garbage this week, in terms of the numbers that they are suggesting.
"Obviously an EU quota system for EU members... well it's obvious we are not an EU member.
"That scheme itself isn't really working very well. So the idea that we're going to join the EU scheme on quotas is complete nonsense. We're not an EU member and that wasn't what I was talking about."
Labour also wants to end the use of hotels for asylum seekers and increase cooperation with Europol to stop gangs from being able to set off small boats from the French coast in the first place. Sir Keir visited officials in the Hague to discuss the plans this week.
Figures from the Home Office at the end of August showed more than 51,000 asylum seekers were being housed in hotels, costing around £6m per day, while the full bill for the accommodation in the last financial year was £2.28bn.
The backlog of asylum claims in the UK hit a record high in the same month, with a total of 175,457 people waiting for an initial decision on their claim.
Speaking from the meeting of centre-left leaders, which include Canadian Prime Minister Justin Trudeau and New Zealand's former leader Jacinda Ardern, Sir Keir also reiterated that he would use serious crime prevention orders on suspected people smugglers.
He said: "We've had serious crime prevention orders for a long time in place in relation to terrorism and other serious offending, and that allows a court to impose restrictions of movement to chase money and freeze money of those involved in organised crime.
"Those orders have never been used to deal with those involved in the vile trade of putting people into the water to cross the channel. And I want them to be used in that way."
Asked about Commons leader Penny Mordaunt's likening of him to "Beach Ken" from the new Barbie film, Sir Keir said it was "water off a duck's back".
After she claimed he, like the character, has "zero balls" and "stands for nothing", he added: "When a government has completely run out of energy and ideas, they go down this rabbit hole of ridiculous insults."
The Labour leader, who will travel to Paris next week for talks with President Emmanuel Macron, also hinted at tax cuts - and sticking to existing commitments on net zero.