David Cameron made the comment in response to a question from Oxford West and Abingdon MP Nicola Blackwood.
Ms Blackwood called on the government and retailers to "make it more difficult" to get hold of weapons.
Justin Skrebowski, 61, was killed in the chain's Abingdon branch on 7 December.
At Prime Minister's Questions Mr Cameron, who represents Witney in Oxfordshire, said he had been "shocked" by the attack and would examine Miss Blackwood's suggestion.
He said: "I think [Miss Blackwood is] right to ask the question about offensive weapons and how available they are and I'm very happy to look at that.
"I also think with that attack and also the Leytonstone attack - although unrelated - it is right also to look at the resources our police have in terms of the equipment they have."
Trevor Joyce, 36, was charged with murder after the attack and is due to appear at Oxford Crown Court on 7 March next year.
Thames Valley Police said it had voluntarily referred itself to the IPCC following the stabbing.
The prime minister has said he will look into the availability of "offensive weapons" in the wake of a fatal stabbing in a Poundland store.