A Sydney prankster pretending to be an Australia Post employee has received death threats after claiming he would throw all same-sex marriage “No” votes in the bin.

Dan Nolan, a self-described “internet idiot”, sparked national outrage on Wednesday when he threatened to read, and subsequently trash, people’s private votes by shining a torch through sealed envelopes.

It comes after significant public concern earlier this week that their vote in the same-sex marriage survey may not be a secret.

Mr Nolan tweeted on Wednesday: “I work at the australia post in chatswood and I’m using a torch to check all ballots and throw out ALL no votes.”

https://twitter.com/dannolan/status/907817752060059648

What followed were deeply-angered responses from voters, who believed the post to be sincere.

“Action must be taken,” Vote NO Australia Facebook page wrote.

“Obviously Dan you have no moral compass of what is right or wrong, you don’t respect democracy and foolishly think you have superior morals,” one Twitter user said.

Mr Nolan also proudly tweeted he had received a death threat.

https://twitter.com/dannolan/status/907889752988311552

Australia Post took action Wednesday afternoon to inform Australians Mr Nolan did not work for the company, and issued a warning to the prankster, tweeting “tampering with mail is a federal offence”.

Australia Post also attempted to douse concerns of a lack of privacy in the marriage equality vote.

“We have strong security measures in place throughout our national network. We have undertaken a thorough review ahead of delivering the survey and will have additional security measures in place during the process,” an Australia Post spokesperson told The New Daily.

“We are also working closely with the authorities to maintain the integrity of the mail network.”

Meanwhile, the Australian Bureau of Statistics (ABS) – the government department in charge of handling the survey – said people shining torches through envelopes was not a security issue.

“Regarding reports of people shining torches through survey envelopes, the ABS does not consider this to be a security or fraud concern,” ABS spokesman Michael Wilson told The New Daily.

“The survey form has no visible identifying information such as a name or address. This ensures that anyone with access to a completed survey form is unable to identify the respondent.”

“The ABS has used envelopes manufactured with a security lining printed on the inside.”