Thousands of teachers and students have taken to streets across Spain to protest spending cuts they say are destroying the country's public education system.

In Madrid, the protesters - many of them wearing green T-shirts that have become a symbol of their movement against the budget cuts - marched to the education ministry on Thursday. The demonstrators called on Jose Ignacio Wert, education minister, to resign.

"We have a small budget and they are reducing it more and more. There are fewer and fewer teachers and more and more students," said Fernanda Gonzalez, 39-year-old high-school English teacher, at the protest.

Students in the crisis-wracked European Union nation perform below EU standards in mathematics and foreign languages.

One-day strike

The protests coincided with a one-day strike by teachers, students and support staff that affected all levels of education.

Organisers claimed a 70-percent turnout by teachers for the strike, while the education ministry put the figure at 20 percent.

Protests were also held in several other cities, including Barcelona, Spain's second-largest city, Seville, Valencia and Zaragoza.

Al Jazeera's Rory Challands, reporting from Madrid, said though many Spaniards agree their education system is in need of reform, the government's proposed changes are not the way to address Spain's shortcomings.

The Platform for the Defence of Public Schools, which groups together students, teachers and administrative staff, called the strike to protest against austerity measures they say are running down the public education system.

They are also angered by a planned education reform, which sets new grading systems, allows for larger class sizes and boosts the proportion of Spanish-language classes at the expense of regional languages.

The education ministry's budget has been cut by 14 percent between 2012 and 2013.

The cuts have caused university tuition fees to soar, led to larger class sizes, fewer grants for graduate studies and cuts to school buses for primary school students in rural areas.