Canadian wireless networks have been hit by major outages that started Sunday and are still resulting in dropped calls and other voice network problems across the country.

Rogers said on its website on Sunday "some customers may be intermittently experiencing dropped calls or are unable to place or receive calls on their mobile phone or wireless home phone service. We are working diligently to restore services as soon as possible. We apologize for any inconvenience and thank you for your patience."

Text messages, internet and data services have been operational, but voice services have been impacted intermittently.

Rogers says its system was mostly restored on Sunday evening, but problems are persisting into Monday on a limited basis.

"Voice services are restoring with a very limited number of customers experiencing intermittent interruption to voice calls," Rogers spokesperson Michelle Kelly told CBC News on Monday. "Teams are working hard to fully resolve the issue and we sincerely apologize to our customers."

Freedom Mobile, owned by Shaw Communications, also said it experienced a similar outage on Sunday and it, too, is not yet fully resolved.

On Sunday afternoon, the company detected "a disruption to our wireless voice network and a degraded quality of service, which included wireless voice calls being dropped and many customers being unable to place or receive wireless voice calls," a spokesperson with the company said.

"Our technicians have been actively managing the network and working to fully restore wireless voice services. Some customers may still experience intermittent wireless voice service. Thank you for your continued patience."

The outage affected 911 calls, with some emergency responders reporting dropped calls and an inability to get through.

Police advised people to use another service to call 911 in case of an emergency. Rogers told CBC News in a statement that 911 access had returned to all customers, as of Sunday evening.

Please be advised the ROGERS network is down globally. Please use a bell provider or landline to contact 911. ROGERS is actively working to repair the issues. —@lpsmediaoffice

Other companies were affected, too, to the extent that their customers had problems on calls involving the two affected networks.

Telus said some of its customers may have issues calling customers on other networks, but calls to other Telus customers should be fine.

"The current network outages are with Freedom Mobile and Rogers, and its sub-brands Fido and Chatr — confirming that it is not a Telus outage," a spokesperson with the company told CBC News.

Bell also said the problems originated on other networks, but any Bell customers calling into another network would have experienced problems.

"Service disruptions on other carrier networks prevented Bell customers from calling or receiving calls from customers of the affected providers," the company told CBC News.