It is already an offence to sell knives to under-18s but the planned measures would mean they cannot be delivered to private property, such as the buyer’s home.
Ministers say this would make it harder for under-age purchases to go undetected following warnings online age verification checks can be sidestepped.
Under the plans anyone who bought a knife on the internet would be required to collect it at a store or another physical premises.
Retailers would be responsible for checking the age of all buyers by asking for them to show ID such as a passport or driving licence.
Arrangements for how online sellers without physical stores can comply will be considered as part of a consultation to be launched later this year.
It is illegal to sell a blade of more than three inches (7.62cm) to anyone under 18 - but reports have suggested safety checks can be circumvented.
Calls for action on internet sales intensified last year after a court heard a knife used in the fatal stabbing of Bailey Gwynne, an Aberdeen schoolboy, was purchased online.
Bailey’s killer, a 16-year-old youth who cannot be named for legal reasons, denied murder and was convicted of the lesser charge of culpable homicide.
Announcing her intention to tighten the law, Home Secretary Amber Rudd said: “We are announcing new measures to combat knife crime and the devastating impact it has on families, individuals and communities.
“We are going to be consulting on new legislation so that people can’t buy knives online without having their identity checked.
“At the moment you have to do it by the click of a button. What we are proposing is that if you want to buy a knife online it has to be collected from a place where you have to show your ID.
“We have evidence that young people have been able to buy knives without verifying their ID and I want to stop that.”
She said it was a “perfectly reasonable” step to take, pointing to figures indicating that almost three-quarters of online retailers which should carry out age verification checks are not doing so.
“The online retailers may say ‘well, we ask people whether they are over or under 18’, and that’s just not good enough because we have the evidence that people have been able to get them delivered to their home,” Ms Rudd said.
In one case an under-18 was able to get a knife by having it delivered to their mother’s shed, the Home Secretary added.
The new drive will also aim to close off a loophole that means police can be powerless to act if they discover knives in someone’s home.
A ban on the possession of outlawed weapons such as zombie knives and knuckledusters on private property would mean officers can seize them and make arrests.
Any restrictions will be drawn up so that those who keep weapons for a legitimate purpose, such as cultural items or antiques, are not penalised.
The consultation will also seek views on whether the offence of possessing a knife in a public place and school premises should be extended to also include the grounds of other educational establishments, such as higher education institutions.
A slew of official data has underlined mounting concerns over rising levels of knife crime.
The most recent national crime figures showed the majority of police forces - 33 out of 44 - registered a rise in offences involving knives and sharp instruments last year.
Police have warned of a shift which has seen the proportion of youngsters carrying knives who are linked to gangs fall.
Officers say youths are keeping blades on them for reasons including “status” and self-protection, as well as crime.