Rio 2016 communications director Mario Andrada said the Brazilian public would not tolerate an overspend.

"The days of lavish spending are over," said Andrada. "We need to be creative in the way we find these savings."

Events across 50 Olympic and Paralympic sports featuring about 15,000 athletes will not be affected.

The BBC understands a crisis meeting has been held in the past few days.

The organising committee's budget is privately financed, with separate budgets for stadiums and infrastructure, but the Brazilian government would have to meet the cost of any overspend.

Ticket sales have been slow with only two million of the five million available sold so far.

"People get upset about luxury and excess, we have to tighten our belts," added Andrada.

At the Confederations Cup held in Brazil in 2013, fans protested angrily at the amount of money spent - about £2.57bn ($4bn) on staging the 2014 World Cup.

What will be affected?

Opening ceremony - approximately three and a half hours long - budget cut. Now estimated to be 10% of the cost of that of London 2012
All promotional videos must now be made in-house
Online lottery for tickets scrapped and all on open sale with the option to pay by instalments
More tents and fewer structures at Olympic events
Infrastructure at test events scaled back
Volunteer programme, which includes English lessons for participants, likely to be cut from 70,000 to 60,000
-BBC