Chief executive of the Local Government Management Agency Paul McSweeny said that he expects a lot of activity next week from people paying the household charge.
Mr McSweeny says there are still one million paper forms in circulation - and many of those will be sent in next week.
The latest figures show that 467,000 households have registered to pay the €100 tax ahead of Saturday's deadline.
Paul McSweeny says the ratio of online to offline registrations is currently running at 83% to 17%, so this could indicate that there are still a lot of paper documents to come in.
"We find it curious that that should currently be the case,"
"We're also aware however that there are still one million paper forms out there in circulation.
"We would expect that quite a number of those are still going to come back, because the ratio of split that we have between online and offline does seem odd to us."