WARSAW, June 11 (Reuters) - Polish President Karol Nawrocki vetoed for the third time a bill regulating cryptocurrencies and implementing European Union regulations because it did not take into account his previous objections, he said on Thursday in a statement.

o Polish lawmakers adopted a bill regulating cryptocurrencies in May, as a scandal involving the collapse of the country's biggest exchange deepened and amid a row over how much to supervise the growing sector.

o The bill implements the European Union's Markets in Crypto-Assets Regulation, which Poland must approve by July.

o Nawrocki had vetoed bills on the subject twice before and said on Thursday that he supported regulating the sector, but the government ignored most of the proposals prepared by his office.

o "I support regulating this market. I support consumer protection, but it must be done effectively," he said. "The bill will be signed into law if it is amended."

(Reporting by Anna Wlodarczak-Semczuk; Editing by Alex Richardson)