New Brazilian President Michel Temer has promised funding by "next week" ©Getty Images

Additional funding, which is vital for the completion of the subway extension linking the Rio 2016 Olympic Park with the city centre, is due to be provided by the Federal Government by "the start of next week", the host nation's interim President Michel Temer has promised.

Although not part of the initial bid for the Games, the new line linking Barra da Tijuca with Copacabana is seen as vital for the flow of spectators during the Games, as well as a major legacy benefit thereafter.

But construction has been fraught with problems, with the line initially due to be completed last year, and then earlier this year, before dates of August 1 and August 2 were given for a limited "soft opening".

More problems emerged after a payment of BRL$989 million (£193 million/$280 million/€246 million) to the state was rejected earlier this month by the Brazilian National Development Bank due to a failure to pay-back previous loans.

This loan was seen as vital to the completion of the line.

“We will collaborate not just with words, but also with the financial needs,” said Temer, who has stepped-in for the suspended Dilma Rousseff who is facing an impeachment trial.

He did not reveal the size of the loan to be given, or if other Olympic-related projects will be supported.

But it was promised “by the start of next week".

The tunnel for the line was completed last week but work remains on several stations as well as final overlay work and testing.

The subway extension is only due to open three days before the Opening Ceremony, and could be pushed-back even further ©Getty Images
The subway extension is only due to open three days before the Opening Ceremony, and could be pushed-back even further ©Getty Images

One of the stations, São Conrado, was reportedly completed yesterday, although it still required the installation of its computer operating systems and final tests.

Concerns remain over the safety of the project, however, given how rushed it has been.

Rio State’s Audit Court gave state rail transport company RioTrilhos one month last week in order to present reports verifying that all testing had been successfully completed.

It was pointed-out that the original contract stipulated a full year for testing, rather than the 60 day period now being adopted.

This "raises doubts about whether there is enough time reserved for all adjustments and tests necessary to carry out a safe and trustworthy operation".

Safety concerns are one aspect after two cyclists died in April after a cycle way linking the same areas collapsed.

“Hurry is the enemy of perfection,” said Audit Court President Jonas Lopes de Carvalho Lopes.

“What matters to us, in this specific case, is the safety of the population.”

If the subway does fail during the Games, the new rapid-bus transit system is expected to be used as an alternative.

All accredited personnel - such as athletes, officials and media - will have access to special Games-lanes, although huge concerns remain about the general transport system.