Epping Forest MP Dame Eleanor Laing has given an update on the situation at Debden Delivery Office and local post deliveries.
Dame Eleanor said: "I fully appreciate the concerns about the deficiencies in the service currently being received from Royal Mail.
"I have been aware of this situation for a considerable time and have been in touch with Royal Mail on several occasions."
Dame Eleanor has had a meeting with the National Service Delivery Director who has given her his assurance that he and his team are doing all they can to improve the service.
Dame Eleanor said: "Let me assure constituents, first and foremost, that letters from the NHS, easily identifiable by the blue NHS logo on the outside of the envelope, are being given priority and are being delivered promptly.
"Anyone awaiting an invitation for the vaccine will receive their letter on time.
"The prioritisation of letters and essential items being sent to and from the NHS is one of the reasons why other mail deliveries are being delayed.
"In addition to urgent letters, Royal Mail have also been prioritising the delivery of PPE equipment and Covid test kits which people have to send straight back to the NHS via priority post boxes."
She added: "The circumstances in which we have all had to operate since last spring have led to a massive increase in the volume of mail in general.
"More parcels are being sent because people do not see their friends and families face to face. More goods are being delivered because we are buying online when we can’t go to shops. The Christmas post, of course, added to the pressures.
"The reason why the situation is particularly bad in our area is that, with infection rates here being amongst the highest in the whole country, the Debden Delivery Office has been hit four times by outbreaks of the virus. Many of the staff have been very seriously ill.
"I have great sympathy for them and for their families. I am sure you will realise that when one employee contracts the virus, every other employee who has been in contact with him has to isolate at home. That isolation has to happen immediately and therefore the delivery office has had to cope with sudden staff shortages.
"The senior directors at Royal Mail have assured me that they are doing all they can to counteract these difficulties and to get your postal service back to normal.
"They are now putting on extra deliveries on Sundays and dealing with the backlog. They have also kept on many of the additional staff who had been employed to deal with the Christmas rush.
"I fully appreciate that you will still be angry that you are not receiving post regularly, but I want to give you a full explanation.
"There is no part of our community which has not been affected by this terrible pandemic. Let us hope that now infection rates are beginning to fall and the most vulnerable among us are being vaccinated that it will not be long before we can return to normal.
"I assure you that I will continue to monitor Royal Mail’s performance and to insist that the service is improved."