North Somerset Council apologised saying waste collection standards ‘must improve’.
Biffa has claimed the delayed collections were a result of staff shortages and vehicle breakdowns.
It has been posting details of potential delays online in recent weeks.
A council spokesman said: "We sincerely apologise for the delayed collections.
"There have been various issues at Biffa, including vehicle breakdowns and staff shortages which has resulted in delays.
"We have been updating the website and social media pages as much as possible to keep people informed about the delays.
"Biffa understands the service must improve drastically and be brought back up to the standard we expect as soon as possible.
"We have seen a much better picture in the past week and we will monitor areas that are experiencing problems."
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