REYKJAVIK, Iceland — Iceland this week began putting in place a new law that requires companies and government agencies to prove they are paying men and women equally, positioning the country at the forefront of global efforts to minimize gender inequality.

The Equal Pay Standard, which was part of broader legislation that was proposed last March and passed in June, took effect on Monday. It says that companies with 25 full-time employees or more must analyze their salary structures every three years to ensure that men and women are being paid the same amount for doing the same jobs. Then they must report back to the government for certification or face penalties that include fines.

While Iceland has had equal pay laws in place since 1961, the new standard is seen as the first time that the small and prosperous nation of about 340,000 has put in place specific steps to try to force companies to eliminate pay gaps.

“Of course it has always been illegal to unequally pay men and women,” Frida Ros Valdimarsdottir, the chairwoman of the Icelandic Women’s Rights Association, said in an interview on Wednesday. “But this is a legally binding tool kit.”