Demon Internet is warning customers to expect disruption to services for six or seven weeks as it finishes an upgrade to its network.

The ISP claims the work is nearing completion with "migration and replacement work to establish all services across the new platform continuing through March, and expected to be completed several weeks later."

Demon claims that during this time there could be "periods when there may be unpredicted interactions between our old and new data platforms that affect the quality of service our customers' experience."

Perhaps that's what was to blame for an outage last week that, according to one Net expert, saw the whole Demon network drop off the screen for half an hour or so.

No one at Demon was available to comment on the upgrade. Demon's help desk was also out of operation.

Apparently, the call centre was evacuated earlier this afternoon as part of a fire drill, although it's understood to be a false alarm. ®