Boats carrying migrants across the English Channel could be turned back from the UK, if personally approved by Home Secretary Priti Patel according to BBC.
The government has authorised Border Force officials to use the new tactic – but only in limited circumstances.
However France is strongly against the plan, saying it breaks maritime law and accusing the UK of blackmail.
But Boris Johnson’s spokesman said any plans would be “safe and legal” and would comply with the law.
Rising numbers of migrants have been crossing the English Channel in recent months – and so far this week more than 1,500 people have crossed by boat.
The Channel is one of the most dangerous and busiest shipping lanes in the world.
Many migrants come from some of the poorest and most chaotic parts of the world, and many ask to claim asylum once they are picked up by the UK authorities.
The Home Office said it continues to evaluate and test a range of safe and legal options to find ways of stopping small boats making the journey.
The prime minister’s spokesman said the same, and that the UK’s activities “comply with international and domestic law”.
And the government added that it needs to use every possible tactic at its disposal to tackle people smuggling.
Ms Patel has repeatedly spoken out about organised crime gangs who smuggle people to the UK for profit – and that the new Nationality and Borders Bill aims to “break their business model”.
She will host the final day of the G7 interior ministers meeting on Thursday, with illegal migration anticipated to be the focus.