It said the funding crunch would affect 300 Cambodian employees, including drivers, prosecutors and judges, unless more funding was found.
The problem has "demoralised each and every one of the national staff," the tribunal's chief administrator Kranh Tony said in a statement.
The tribunal has been frequently cash-strapped since it was set up in 2006 to find justice for the deaths of up to two million people under the hardline communist Khmer Rouge regime in the late 1970s.
It relies on donor aid to pay all its salaries. In late 2011 the court ran out of funds to pay hundreds of Cambodian workers until it received new funding from Japan in March.
The Cambodian side of the hybrid court needs $9.1 million to operate in 2013, but has received no new funding pledges from donors, the court said.
"It is a serious concern for the court and its staff," tribunal spokesman Neth Pheaktra said.
The UN side of the court has enough in its budget to run through February, he added.
The tribunal has long been dogged by allegations of political meddling by the Cambodian government and has also been criticised for proceeding too slowly, adding to donor reluctance to hand over more cash, say observers.
The court suffered a new setback earlier this week with the resignation of three international lawyers who complained of political interference.
The court, which has spent more than $153 million since it was set up, has so far achieved just one conviction, sentencing a former prison chief to life in jail for overseeing the deaths of some 15,000 people.
The trial of the regime's three top surviving leaders is ongoing.