MORE DETAILS: What is causing Telstra outages in Ballina?
RESIDENTS in Ballina, Lennox Head, Wardell and parts of Alstonville may not be able to use their mobile phones during Telstra's 'planned maintenance'.
While Telstra's website says the work is estimated to continue until at least Tuesday night, the regional general manager, Mike Marom, said much of the work had already been completed.
"Telstra has this week been undertaking an upgrade on some of its mobile infrastructure in the Ballina area to improve coverage and capacity on the 4G network and also upgrading the towers in preparation for the arrival of 5G services," he said.
"This has resulted in a temporary decline or loss of mobile coverage for some parts of the community while work has been underway.
"Fixed line telephones and nbn services have been unaffected and there remained some mobile coverage in parts of the community.
"Unfortunately there is never a perfect time to do network upgrades and we work as quickly as possible to reduce the impacts on the local community."
Telstra advises the upgrade work should be completed today and coverage levels in some areas have already returned.
But some locals are not impressed.
Many have expressed concerns on the Ballina Community Noticeboard Facebook page.
Lynne Dollery: "They told me the lines are being upgraded for 5G."
Maria Stratton: "Ballina is growing and this so-called progress is slowing the town's networks. We need more resources."
Chloe Afflick: "I have nothing with Telstra in East Ballina pretty much all the way to Lennox."