Some asylum seekers arriving in the UK via small boats or the back of lorries are being electronically tagged as part of a Home Office trial programme.
Under the system, those tagged may be subject to a curfew or excluded from certain locations.
The department said the 12-month pilot, which began on Wednesday, will test whether electronic monitoring is an effective way to give immigration bail to asylum seekers who arrive in the country using "unnecessary and dangerous" routes.
The Home Office said the trial will test whether tagging aids regular contact with migrants given bail and progresses their claims more effectively.
Boris Johnson, quizzed on the policy on Saturday, said it was about ensuring "asylum seekers can't just vanish into the rest of the country".
Labour leader Sir Keir Starmer accused the government of "chasing headlines" with the plan and called for a "serious response".
"I absolutely want to see us clamp down and end the trafficking, the criminal gangs, that are running this.
"That requires a grownup, serious response, working with the French authorities, and tracking down the gangs upstream. I don't think the government's plans are going to achieve that," he said.
It comes after the European Court of Human Rights (ECHR) on Tuesday granted an injunction that resulted in a chartered aircraft to Kigali being unable to depart Wiltshire.
The ruling prompted Home Secretary Priti Patel to accuse the court, which is not linked to the EU, of being politically motivated.
Individuals tagged will have to regularly report in person to authorities, may be subject to a curfew or excluded from certain locations, and failure to comply could see them returned to detention or prosecuted.
It's not clear how many people will be tagged.
A Home Office spokesperson said: "The government will not be deterred as we plan for the next flight to Rwanda.
"We will keep as many people in detention as the law allows but where a court orders that an individual due to be on Tuesday's flight should be released, we will tag them where appropriate."
It comes after new figures revealed the number of people crossing the Channel to reach Britain this year has passed 11,000.
Analysis of Ministry of Defence data by the PA news agency shows 11,092 people have been brought to shore by Border Force or the RNLI after being rescued from small boats in the Channel, the world’s busiest shipping lane..
The daily number has been decreasing steadily throughout the week after a high of 444 on Tuesday. That was the highest number since 562 on April 14.
At least 48 people were brought ashore at Dover on Thursday, including women and children as well as adult men.
Warm weather and calm seas this week may have encouraged an increase in attempted crossings.