Patrol vessels will be brought back from overseas to the Channel as part of efforts to stem migrant crossings to UK shores via small boats.
Two Border Force cutters will be redeployed, Home Secretary Sajid Javid has announced, after he led a cross-government meeting on Monday in response to what he has declared a "major incident".
The latest crossing over the festive period saw 12 Iranians – including a child – land on the beach at Lydd-on-Sea, Kent, at 6am on New Year's Eve.
The Home Office released figures to reveal 539 migrants have attempted to travel to the UK on small boats this year, with around 80% making their attempts in the last three months of 2018.
Of the total number of attempted crossings, 42% were intercepted by French authorities before they made it to the UK.
In December, around 230 migrants attempted to cross the Channel but just under half were disrupted by the French authorities and never left the French coast, Mr Javid added.
The home secretary, who cut short a family holiday to deal with the situation, had been under increasing pressure from fellow Tory MPs to step up the government's response.
After Monday's meeting, which was attended by senior officials from the National Crime Agency and Border Force, Mr Javid said: "This incident around the Channel remains a very serious concern to me, and that's why I declared it as a major incident a few days ago.
"It's both about protecting human life but also about protecting our borders. When it comes to human life, clearly I want to make sure that we are doing all we can to protect people.
"We must remember that this is one of the most treacherous stretches of water that there is, 21 miles with people taking grave risk, really putting their lives into their own hands by taking this journey."
He added: "I have made a decision today to redeploy two of the Border Force's largest vessels, known as cutters, from abroad back to the UK, to south east England, and they will be joining a cutter that is already there and two other coastal patrol vessels.
"This will help both with the human side of this situation but also to better protect our borders."
Mr Javid also outlined an intent to step up action to tackle people traffickers, to increase the rate at which migrants are disrupted from even beginning their crossings from the French coast, and to work with the French on returning some of those people who do reach the UK.
He admitted there is not "one single answer" to the situation but that action was required on "many fronts".
Previously, immigration minister Caroline Nokes had signalled a Home Office reluctance to put further Border Force vessels in the Channel.
On a visit to Dover at the weekend, she claimed more craft could act as a possible "magnet" for further attempted crossings.
However, Mr Javid said there was a "balance to be struck in terms of patrolling our waters" after announcing the redeployment of the cutters.
"There is a human side to it in that if you do come across anyone in distress, in a difficult situation, of course our officers will act and do the right thing," he added.
But, sending a "strong signal" to those considering a crossing attempt, Mr Javid said: "We will do everything we can to make sure it is not a success.
"I don't want people to think if they leave a safe country like France, they can get to Britain and then just get to stay."
Dover and Deal MP Charlie Elphicke welcomed the government action. He told Sky News: "I've been calling for the return of the cutters from the Mediterranean for some time.
"I'm delighted that the home secretary has listened and has brought them back.
"Now what we need is to form them into a modern Dover patrol to act as an effective deterrent – working in a new compact with the French – to make sure that anyone trying to cross the Channel is returned safe and secure to the coast of northern France."
Mr Elphicke added: "My greatest concern is that, if we don't bring this crisis to an end, sooner or later there will be a tragedy in the middle of the English Channel."
The Border Force has a total of five cutters and six coastal patrol vessels (CPVs).
One cutter, HMC Vigilant, and three CPVs are currently deployed in the Channel, with cutters HMC Valiant and HMC Protector in the Mediterranean.
HMC Seeker is in Gibraltar while HMC Searcher remains in UK waters.
One cutter will be retained in the Mediterranean in order to fulfil the UK's commitment to the EU's humanitarian mission.
The Home Office confirmed on Monday the group, presenting themselves as Iranian, who landed at Lydd-on-Sea consisted of nine men, two women and 10-year-old child.
Earlier on Monday, writing in the Daily Telegraph, Mr Javid said ministers would "not stand by and allow reckless criminals to take advantage of vulnerable people".
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He cited instability in the Middle East and North Africa, increased security at Calais to prevent stowaways on lorries and ferries, as well as organised criminal gangs for "profiteering from these vulnerable and often desperate people".
Mr Javid also paid tribute to joint UK-French efforts to deal with migrant crossings, after holding a telephone call with his French counterpart Christophe Castaner on Sunday.