Suharto was conscious on arrival at hospital
Suharto earlier regained consciousness after falling ill at his home at the weekend, but still had trouble breathing.
The 80-year-old former general was conscious on arrival at the Pertamina hospital but had an intravenous drip inserted in his nose. One unnamed aide said he was suffering from a high fever.
Mr Suharto ruled Indonesia with an iron fist for 32 years before being forced out of office in 1998 amid riots and pro-democracy protests.
He is accused by critics of amassing a multi-billion dollar fortune during that time, but the Supreme Court said last week he was too ill to ever go on trial.
Mr Tampubolon said Suharto's condition had been made worse over the weekend because he continued to fast during the last days of Ramadan.
Son's appeal
Critics of the Suharto family have questioned how ill the former president really is, saying this could be a ploy to allow his youngest son, Hutomo "Tommy" Mandala Putra, out of custody to visit him.
Tommy Suharto was arrested in November after more than a year on the run after failing to hand himself him to start an 18-month prison sentence for corruption.
That conviction was overturned but police are now questioning him in connection with a judge's murder and a series of bombings.
Tommy Suharto's lawyer Elza Syarief said she had sent a letter to the Jakarta police chief asking him to allow Tommy out for a visit.
"So far there has been no answer from the police," she said. "My client has the right to visit his ailing father."
Mr Suharto was rushed to hospital in June after collapsing at home with low blood pressure and an irregular heartbeat. He was treated and fitted with a pacemaker.
Since leaving office, he has also suffered about three strokes which doctors said had caused him brain damage.