Fredrik Wallin was responding to claims on website TMZ, reportedly from a US Embassy official, that walking into Kronoberg prison is like “walking into a toilet”.
The website had claimed the rapper is being held in a “disease-ridden” prison where the food is “inedible”.
ASAP Rocky was arrested last week on suspicion of assault.
He’s being held while Swedish authorities investigate a fight he’s alleged to have been involved in.
Mr Wallin told Newsbeat he’s not able to comment on individual prisoners.
“However, I am able to talk about the general conditions in the remand prison which apply to all prisoners,” he said in a statement.
TMZ’s report mentioned Rocky being held in a cell next to someone with “severe mental issues who slams his head against the concrete wall and hurls faeces every which way… faeces that are not cleaned up”.
A source reportedly told them he was being made to sleep on a yoga mat with no blanket, drink water that was not clean, and had only been given an apple to eat each day during his first five days at the prison.
Separately, ASAP Mob member ASAP Ferg claims Rocky is being held in solitary confinement.
The claims have led to concern among ASAP Rocky’s friends and fans, as well as a petition to free him.
But Mr Wallin says prisoners at Kronoberg normally live in cells that contain a desk, a bed with a mattress, and a TV.
He says the prison was renovated in the last few years, with all the prison cells being reconstructed, leaving the prison in “good condition”.
“I have no knowledge on any current diseases in the remand prison,” Mr Wallin told Newsbeat.
The governor says that all prisoners in Swedish remand prison – where people stay while awaiting trial – receive three meals each day, and that a professional cleaning company “immediately sanitises” and cleans an area following food spillages or accidents that result in blood.
“This is done for the sake of the prisoners as well as for our staff, for them to have decent working conditions.”
Swedish remand prisons do contain some solitary cells – but the Swedish Prison and Probation Service says they’re not commonly used and can only be reserved for violent prisoners, after a formal written decision has been made.
ASAP Rocky is being held in prison while Swedish prosecutors investigate a fight he was allegedly involved in.
The American had been in Stockholm to perform at a festival, but was arrested afterwards.
Video posted to his Instagram account showed Rocky and his crew asking two men to stop following them.
One of the men accused the 30-year-old’s team of breaking his headphones.
In the caption for the first video ASAP Rocky wrote: “We don’t know these guys and we didn’t want trouble. They followed us for four blocks.”
In the second, he accuses the man of hitting his security guard “in the face with headphones”.
A separate video published by TMZ following his arrest reportedly showed Rocky punching someone.
On Friday, following a hearing, Swedish authorities decided to keep Rocky in custody for an extra two weeks while the investigation is ongoing.
It meant the rapper couldn’t attend Wireless festival in London, where he was headlining. He’d already missed scheduled slots at Longitude in Dublin and Open’er Festival in Poland.
That reportedly represents a more than $1 million loss in earnings for the rapper.
Swedish authorities have the option of detaining Rocky for a further two weeks – after another hearing – if the investigation isn’t completed during the time they initially requested.
The situation has led to friends of ASAP like Tyler, The Creator, ScHoolboy Q and Lil Yachty saying they are boycotting the country.
Tyler is going on tour later this year, which includes two dates in London (where he’s recently had a ban overturned), but no other European dates.
Newsbeat has contacted ASAP Rocky’s team and the US Embassy in Sweden for comment.