It comes even though there has been a largely incident-free opening two days on the subway line extension westwards to Barra de Tijuca.

The line, which opened yesterday for accredited personnel following huge delays and concerns it would not be ready in time for the Games, reduces journey times considerably.

Roads are more congested that ever, however, due to the implementation of Olympic Games-lanes.

Average speeds during morning rush hour are as low as 15 kilometres-per-hour, Globo reported, with 20km of traffic jams,

Transport routes around the main Olympic hub of Barra de Tijuca are particularly affected, as well as an Ipanema close to the Lagoa Rodrigo de Freitas rowing and canoe sprint venue.

Many unaccredited cars are also driving in the Olympic lanes, despite the risk of fines.

There appear to be few security forces present to keep them out of the lanes.

If this is not resolved by the time competition begins, this raises the prospect of athletes being late for events.

"We are not concerned about that - it's normal,” Rio 2016 communications director Mario Andrada told insidethegames.

“It takes a little while for the public to realise that they will be fined every time they cross [into the lanes].

“In some aspects, the Olympic lanes are not too visible, with the green colour.

“Transportation takes a little while, maybe one day, to be fully operational.

“There has not been a Games in history that has not needed fine tuning with its transportation."

Organises hope the start of the school holidays during the Olympics will help reduce levels.