Harrow people can post letters and use post office services until later at a new branch.
Brent North MP Barry Gardiner opened the new branch in Preston Road, Harrow, last week.
Mr Gardiner, who opened the new shop, said: “I welcomed the news that Preston Road Post Office was to be modernised to create a bright modern open-plan branch and am delighted to be here today to congratulate Theiva Selvendran on her hard work and to formally declare the new Preston Road Post Office open."
He added: "The Post Office is vital to the community around Preston Road and I'm sure the new improved office, and the longer opening hours, will be warmly welcomed by all of my constituents."
Preston Road Post Office will be open for 60 hours a week, from 8am until 8pm, Monday to Saturday and 10am to 5pm on Sunday.
Post Office operator Theiva Selvendran said: “I was delighted to have the opportunity to open the new branch and I am very pleased to be officially launching it today for the community.
“I hope our customers like their new Post Office and I’m thrilled Barry Gardiner has found time in his busy schedule to come here today. I'd like to sincerely thank my staff for the success of this Post Office.
“They have been a great support to me and I would not be here without them. I’d also like to thank the local community for their continued support and use of the branch.”