Telstra Group (ASX:TLS) said around 90% of calls and data are now flowing across the network as it made progress restoring services following an outage, according to a statement on Wednesday from a Telstra spokesperson.

The company apologized for the disruption and said that its teams are working to restore the remaining services. Telstra had earlier said it was investigating an outage that impacted some mobile calls and data connections.

The issue impacted hundreds of traffic lights in South Australia and resulted in the suspension of regional train services in Victoria and New South Wales, according to media reports.