Women across Spain went on strike and held hundreds of rallies to protest against gender inequality today, leading to the closure of many main roads and squares.

Authorities did not say how many participated in Spain's first nationwide female strike held on International Women's Day, but the two largest unions said around six million women took part.

Organised by "Comisión 8M", a forum made up of feminist groups from across Spain, the strike drew support from all Spanish labour unions.

"I lived under dictatorship, I've lived under democracy and we haven't made much headway. A lot remains to be done and we in the education sector have a big role to play," said Concha Noverges, 50, a teacher on a picket line at a school in Madrid.

Hundreds had kicked off the action in the capital with a pot banging protest at midnight on the Puerta del Sol central square.

Several more protests were held in city squares in Madrid and Barcelona throughout the day and hundreds of thousands of people took part in 300 rallies in more than 200 cities and villages across Spain.

Local police in Barcelona said that around 200,000 people had taken part in the rally in the Catalan capital.

Spain is ranked 27th in a list of 188 countries in the United Nations' latest Gender Inequality Index.

However, Spanish women's access to the labour market remains well below the European average because of the lack of state support.

Women, rather than men, are also often expected to leave their jobs to care for their children or ageing parents.

In Bilbao in northern Spain, thousands of women gathered near the city's famous Guggenheim museum, holding signs with slogans such as "Justice!", "Fight like a girl" and "Revolution."