SAO PAULO, Jan 11 (Reuters) - The release of Brazil's benchmark exchange rate, called the Ptax, was delayed on Thursday during another work stoppage by employees of the country's central bank.

Companies, individuals and foreign firms doing businesses in Brazil use the Ptax as the benchmark exchange rate quotation to settle everything from international credit card purchases to imports and bond payments.

On days when trading occurs, the central bank usually releases the Ptax by early afternoon, about 1:10 pm local time.

However on Thursday, it had yet to do so by 4:30 p.m. local time. Fabio Faiad, president of union SINAL, which represents workers from the central bank, told Reuters this is a consequence of the stoppage.

The central bank did not immediately respond to a Reuters request for comment about the delay in the release.

Employees from the central bank have been carrying out work stoppages since last year in a bid to force the government to address demands related to career improvement.

The Ptax is calculated by the central bank as the weighted average rate for all spot currency transactions during a daily trading session. (Reporting by Fabricio de Castro; Writing by Andre Romani; Editing by David Gregorio)