The average monthly salary of women working full time in top roles in Sweden's municipalities is now 58,925 kronor ($6,951) a month, compared with 57,925 kronor ($6,833) for men, research for Swedish magazine Dagens Samhälle has revealed.
"When municipal managers are recruited, there have recently been clearly more women than men. Because the women got their jobs later [in life] that explains why wages are higher," Staffan Isling, president of Kommundirektörernas förening, Sweden's organization for leading municipal staff told the publication.
The president was alluding to union rules which see staff pay rising incrementally in local government jobs as well as when workers are promoted to the next grade.
However, Anna Elias, another spokesperson for municipal leaders argued: "I think it shows that female managers have become better at negotiating wages. They are often better educated than men, we know."
Stockholm's mayor, Karin Wanngård, earns 125,000 kronor a month. She told Dagens Samhälle that this was based on a general rule that mayors in the Swedish capital earn around 80 percent of what their ministerial counterparts take home and strongly defended her large pay cheque.
"I lead the nation's capital and I am responsible for a budget of 43 billion kronor."
The data has emerged amid strong debates about gender equality in Sweden where other recent studies have suggested the country is now stalling on the issue despite previous rapid advances compared to other countries.
The number of men in parliament has gone up in two consecutive elections, as has the number of men in parliamentary committees and as committee chairpersons. Three-quarters of all board members of listed companies are men and 77 percent of professors in higher education are men.
Across Sweden, women's salaries have stayed at 93 percent of men's salaries since the mid-1990s.
Last year the government suggested that Swedish companies could face penalties if they didn't comply with proposed government legislation designed to ensure boards of directors have a 40 percent female representation in future.