Parcel firms will have to tighten up their complaints handling after the industry watchdog said almost two thirds of customers had experienced problems with deliveries in the last three months.

Ofcom said people sending and receiving parcels should be treated fairly by delivery companies and that around a quarter find it difficult to make a complaint or contact a courier when their delivery goes wrong.

It said it would also look to provide better protection for disabled customers, who are almost 50% more likely to experience significant problems with deliveries. And Ofcom threatened enforcement action or further regulation if it did not see substantial improvements in customer service and complaints handling.

The watchdog’s proposals came after Citizens Advice found problems in customer service and deliveries and major issues with consumers unable to get the help they needed – research parcel firms rejected as flawed and based on poor methodology. Ofcom said its evidence suggested inconsistent levels of service across the industry.

Lindsey Fussell, Ofcom networks and communications group director, said: “Parcel deliveries have become increasingly important to our daily lives and customers rightly expect a positive experience.

“We’re planning to strengthen our rules to make sure people are treated fairly by delivery firms.

“If we don’t see significant improvements in customer service, we’ll consider enforcement action or tighten regulations further.”

It said its additional guidance would set out: who customers could contact and what channels they can use to make a complaint; what the complaints process would be and how long it would take to resolve; and how the complaint must be dealt with by staff with appropriate training.

Hermes said it welcomed the proposals; a spokeswoman said they were “in line with steps we are already undertaking to improve the consumer journey.”

DPD said Ofcom’s research pointed out that the vast majority of parcels were delivered safely and correctly:

“For DPD, this is well over 99% of all deliveries,” said a spokesman. “Naturally, we will review the proposals in detail and continue to support Ofcom’s work to improve standards across the sector.”

Ofcom said Royal Mail was subject to more regulation than other postal operators and that the rules and safeguards were generally working well.

However, it added: “While the short-term sustainability of the universal service appears to be more secure than it was, the longer-term outlook remains uncertain.

“Royal Mail must adapt to the changing market, modernise its parcels operations and become more efficient, if the universal service is to be financially sustainable in the longer term.

“We continue to be concerned about Royal Mail’s efficiency performance. To increase our understanding of its longer-term sustainability outlook for the universal service, we propose requiring the company to set out its longer-term efficiency ambition and report publicly on progress against this.”

Royal Mail said it noted Ofcom’s findings. “However, we are disappointed that Ofcom has not taken this opportunity to allow Royal Mail to offer tracking on USO [universal service obligation] services,” said a spokeswoman. “Consumers increasingly demand more visibility over their deliveries.

“We have requested the ability to offer tracking on USO services so that we can deliver better outcomes for all customers, in line with Ofcom’s stated goals.”

A Yodel spokeswoman said: “Providing an excellent service for customers as eCommerce grows further remains our priority and we support Ofcom’s consultation that will help to ensure high standards are upheld across the industry.”