"The contribution of public resources is small compared to the importance of the event," the president's Chief of Staff Eliseu Padilha said on Tuesday.
Interim President Michel Temer may earmark up to 100 million reais ($30.3 million) for the September 7-18 event, Xinhua news agency quoted him as saying.
The Organising Committee of the Rio Olympic and Paralympic Games requested the government's help following slow ticket sales -- only about 17 per cent of seats have been sold -- and due to a lack of sponsors.
Last week, the committee said it needed at least 250 million reais ($75.8 million) to provide the "level of service" it was committed to offering.
According to Padilha, the committee needs at least 400 million reais ($121.2 million) to cover its expenses, and pledged to look for another 150 million reais ($45.4 million).
The government considers the Paralympic Games to be as important as the Olympics that preceded them, said Padilha, noting Temer is due to attend the inauguration ceremony.
The committee is expecting Rio's city government to provide another 150 million reais.
Rio Mayor Eduardo Paes said the public funds are necessary as both the national and city governments are guarantors of the events, in keeping with the agreements reached with the International Olympic Committee (IOC) when it granted Rio the rights to host the events.
However, Paes was optimistic about ticket sales picking up, saying the sale of seats for Olympic events also began slowly but accelerated as the dates near.
