Images released by the team at the Southwell Post Office shows the extent of the damage.
Police believe offenders used a chain saw to break into a Post Office in Southwell and steal cash.
The incident at the Post Office cash machine in Queen Street happened at about 5.25am on Friday January 11.
Read more: Thieves 'used chain saw' in Post Office cash raid
Posting on social media a spokesman for the Post Office, said: "Once we were allowed into the building the internal damage from the explosion is greater than what we expected.
"We need to make the office safe and secure before we can open.
"This involves work from contractors to replace shattered windows, damaged shelving, ceiling, walls, doors and floors.
"We do not anticipate completion of this until at least Friday 18th January but we will keep you updated on the progress.
"We would like to thank you for the kind messages and continued support."
It is not yet known if the incident is connected to a number of similar incidents across Nottinghamshire.
A spokesman from Nottinghamshire Police, said: "It’s believed offenders used a chainsaw to get into the property and a gas canister to gain access to the machine before taking the cash from inside."