Safety problems at the stadium hosting the World Cup opener in Brazil were being ignored so work could finish in time for the tournament, a Labour Minstry has warned.

Inspectors were "looking the other way" so the already-delayed Arena de Sao Paulo stadium would be completed before the June 12 game, said Labour Minsitry superintendent Luiz Antonio Medeiros.

Officials halted the installation of 20,000 temporary seats, saying new safety measures had to be implemented following the death of a 23-year-old worker a week ago.

Inspectors were at the venue on Thursday but there was no decision on when the work can resume.

Organisers expect the interruption to end next week, which would not significantly affect the completion in time for the match between Brazil and Croatia. Fifa expects the venue to be ready in mid-May.

Fast Engenharia, the company in charge of the temporary seats, said it gave officials everything they requested to show the work site was safe.

"We will only allow the work to resume when we are sure that lives are not at risk and workers are safe," said Mr Medeiros.

"If it wasn't a World Cup stadium, officials would have reported precarious work (conditions) and would have halted the construction."

He said complaints would "delay the work even more."

The Labour Ministry downplayed the comments, saying inspections were conducted, especially after last year's accident that killed two workers when a crane collapsed.

And Sao Paulo prosecutors released a statement pointing to irregularities at the Itaquerao stadium, saying it could close the venue "even during the World Cup" if problems weren't fixed.

They said they could partially close the venue if organisers don't address a long list of irregularities presented by civil defense officials. The irregularities were not specifically related to the area where the worker died last weekend.

The Itaquerao was one of the stadiums that was not ready by the end of last year as expected by Fifa.