Indonesia's communications and information ministry has shut down more than one million pornographic websites ahead of the Islamic holy month of Ramadan.

Minister Tifatul Sembiring said Wednesday that his office would target more sites in the upcoming month.

The closed websites were all run from abroad, he said.

"We will block more porn sites during Ramadan, though that doesn't mean that we will allow such sites to operate during the rest of the year," the minister said.

The minister said there were around two billion websites providing pornographic content, and that public involvement in curbing online pornography was crucial.

"Online pornography is an industry and the producers always seem to find new ways of escaping detection," he said.

Ramadan is due to start July 19 in Indonesia.