A Citizens Advice survey revealed 16 million people received late mail over Christmas.
Business and Trade Minister Chris Bryant informed Dame Harriett Baldwin, MP for West Worcestershire, that a meeting between ministers and Royal Mail had not yet taken place but one is planned for next week.
She said: “For months my constituents have had to put up with late or undelivered mail and to learn that the Government is only stepping in now is worrying.
“Royal Mail assured me before Christmas that they were experiencing local resourcing issues caused by unforeseen demand for parcels and staff sickness.
“However it has now become clear that this is a nationwide problem and I am concerned that the Government has dragged its heels in intervening to secure a long term solution.
“I continue to raise individual complaints with Royal Mail but the Government and Ofcom need to take action against Royal Mail if it does not begin fulfilling its Universal Service Obligation quickly.”