The Post Office is to start the roll-out of contactless "tap and go" payment technology to its 30,000 counter positions from next week.
Terminals enabling people to make small payments with just one swipe will be made available across the network of more than 11,500 branches, making transactions faster and more convenient, the Post Office said.
The "cutting edge" scheme will initially be launched next Wednesday in almost 200 branches around various Olympic sites and is expected to be completed by the end of October.
The Post Office said the initiative will be the largest deployment of contactless technology in Europe and will put the terminals within three miles of 99% of the UK population.
Contactless schemes allow customers to make small payments by tapping their card on a reader at the point of sale without the need to sign or enter a pin number.
Once installed, holders of MasterCard PayPass or Visa payWave cards will be able to use the system in all Post Office Limited branches across the UK, with a limit of £20 per transaction.
The Post Office said the technology is well suited to businesses which need to offer a quick service to customers who need to make low value payments.
Customers will be able to use the contactless system to buy products and services which might otherwise involve a debit or credit card, such as sending a parcel.
A Post Office spokesman said the move is part of its modernisation programme and is being put in place to give customers more choice and greater convenience.
He said it is not being introduced specifically to cut queues as in many branches they are not as prevalent as in the past, due to initiatives such as longer opening hours. But he added: "If it reduces queues, that's fantastic."