AUSTRALIA Post has assured its customers all mail has been delivered "correctly" to a unit block in Sherwin Avenue, Castle Hill.
A spokeswoman said two complaints were received from a customer about mail going missing from a unit in the block.
Click here to read about a man who has been charged with more than 200 documents stolen from homes in Castle Hill, Baulkham Hills, Kenthurst and Lane Cove.
"The mail was delivered safely and correctly," she said.
Her comment follows reports by Castle Hill police that they visited the unit block three times in three months over complaints of mail going missing.
The Hills crime manager, Detective Inspector Gary Bailey, said "a number" of letterboxes were "raided" in Sherwin Avenue from November 22 to December 9.
"Some of the people have had to be spoken to and had their bank accounts checked," Detective Inspector Gary Bailey said.
He encouraged anyone with information about the mail thefts to call the police. Rudolf German, of Hume Avenue (perpendicular to Sherwin Avenue), had to change his letterbox lock after his mail was stolen before Christmas.
"I had no idea it was gone but police returned my Christmas cards in a police envelope," he said.
"It's an invasion of privacy and not the best feeling to know it's happened to you."
A Sherwin Avenue resident, who wished to remain anonymous, said it's "difficult" to know if your mail has been stolen or not.
"A lot of times I see mail sticking out of the letterboxes and next thing you know the wind is blowing the letters along the street," she said.
The Australia Post spokeswoman said: "Letterboxes should feature a mail slot wide enough to fit your mail through, but not so large that a hand can reach inside.
"We also recommend residents keep their letterboxes secure with a sturdy lock."
During two non-related incidents police charged two men with mail theft on January 7.
One man, aged 38 with no fixed residence, was caught with alleged stolen mail from houses in Castle Hill, Baulkham Hills, Kenthurst and Lane Cove.
The other, a 19-year-old from Castle Hill, was under investigation for mail theft from homes on Purser Avenue, Castle Hill.