The accusations were made at a meeting held at the Ackrill Media Group offices in Cardale Park, Harrogate, on Tuesday which was chaired by editor Jean MacQuarrie.
Representatives of Harrogate's business community called for a reliable service with regular delivery times.
Brian Dunsby, chief executive of Harrogate Chamber of Trade and Commerce, said all businesses in the town needed a reliable 9am delivery service to allow them to process and act on the day's correspondence within the normal working day.
"A wide range of businesses are being seriously affected by the late delivery of mail," he told the meeting.
"Harrogate is a professional services town and it needs a professional postal service."
Ralph Zoing, of wealth management business Marshall Zoing Ltd, based on Victoria Avenue, said that although there had been a slight improvement in mail delivery services in recent weeks the service was still unreliable and arrived at different times from one day to the next.
He said the time-critical nature of investments meant it was important for documentation to arrive promptly.
"There are days when we receive mail shortly after 10am but even that is too late for us and there are days when it doesn't arrive until after 12."
Sebastian Rowe, of the Broker Network, said his company was one of the top 10 in Harrogate in terms of volume of mail received and staffed its post room from 8.30am to cope with the workload. Late deliveries meant staff were unable to start sorting post until later and all aspects of the business had suffered as a result.
Broker Network now pays £10 a day to receive its mail at 8.30am but this service had not run smoothly either. Mr Rowe said frequent phone calls had been made by his company to Royal Mail to sort out problems, which included mail not arriving at all or only half of it arriving on time and the rest being left until the following day.
The meeting highlighted a simple wish list from Harrogate businesses. Firstly, they wanted a reliable delivery service with mail arriving at the same time each day. Secondly, they wanted their mail to arrive by 9am to give them chance to process it during the working day and ensuring important items were received at the start of the day.
The Harrogate Advertiser contacted Royal Mail with comments from the meeting and the Harrogate business wish list.
But Royal Mail insisted the situation was unlikely to improve.
In a statement to the Harrogate Advertiser a spokesman for Royal Mail said mail for the Harrogate postcode area was sorted in Leeds and final mail did not arrive at the Harrogate delivery office until 9.45am each day.
He brushed off criticism that Harrogate businesses were suffering severe disruption as a result of the late deliveries, reiterating that the Royal Mail was under no obligation to make deliveries at a specific time.
"Royal Mail's delivery obligations are agreed with our regulator, Postcomm," he said, adding the previously stated response that customers could pay for a timed delivery or collect their mail from the delivery office themselves after 8.30am.
"Our postmen and women in Harrogate are working extremely hard to ensure we meet the needs of all our customers. We cannot, however, guarantee the same delivery times each day, due to the fluctuating volumes," the spokesman added.