AROUND 670,000 Australians have forgotten to hit the send button after filling in their Census forms online.

Paul Lowe, head of the Population Census Program, said many households completed their eCensus questionnaires, but failed to submit them.

Mr Lowe said more than two million households logged onto the online form, with more than 100 submissions arriving every second at peak time, but 670,000 failed to arrive.

He's urged anyone who used the online form to log back on and hit "send".

The first data from last night's census will be released in June next year, revealing, among other things, the contentious issue about who does the most housework.

Originally published as Thousands tripped up by online census forms