German parents are voicing frustration as kindergarten teachers stage running strikes for a sixth straight week, demanding higher pay and increased personnel in pre-school care, according to dpa. Germany may have invented the kindergarten - the German word was taken over into English - and its daycare has been the envy of the world, but workers say all is not well among the sandpits, poster paints and toys. This week, 30,000 kindergarten staff from around Germany skipped work to attend a noisy demonstration in the western city of Cologne, protesting at conditions in municipally operated daycare centres. Like their infant charges, the demonstrators blew whistles and waved rattles, but trade union leaders called it one of the most serious fights in the history of German education, aiming to end a tradition of low pay at kindergartens. Parents, and the children themselves, are starting to get fed up with the long-running dispute. Support among parents for the teachers is falling, and some lawyers have encouraged parents to sue for a refund of fees. The kindergartens employ qualified teachers, untrained assistants and social workers who focus on children's social skills and countering the harm from poverty and dysfunctional families. The strikers are demanding better pay and better health care: work in kindergartens can be unhealthy, and it's not only the germs. "We know this is disrupting the parents' lives more and more," admitted a Cologne teacher, 41. "But we have to fight this one to the end. I've been working in a kindergarten for 20 years. Every night it's the same: I'm exhausted and I can't relax with my own kids. "If our hours and staffing don't improve, I'll collapse." Katja Brieske, who came from the central county of Giessen to demonstrate in Cologne on Monday, said, "The pay does not reflect the fact that we are actually teachers. We are educating the next generation who are the future of our country. "Yet we are earning only a minimal wage." A teacher from Stuttgart wore a T-shirt to the demonstration saying, "I love my work, but I don't do it for love." She said she obtained her full-time job three months ago and receives just 1,300 euros (1,800 dollars) per month after tax, far less than a German mail deliverer for example would earn. In the mid-town march, Gabriele Kopec from the central town of Hattingen, said, "The daily pressure and the demands of the job have grown enormously. We need more staff and a healthy working environment. That would benefit the kiddies as well." A 31-year-old teacher added, "Our job demands a teacher's complete emotional resources and skills. It's draining." Reducing numbers in each teacher's group of children, noise- proofing and upgrading rooms, and providing modern equipment could help too. Banners at the rally declared, "We're worth more than we're paid," "100% trained, 100% work, 0% respect." National politicians showed up and voiced support but they do not administer kindergartens, which are operated within from municipal budgets. Daycare fees are means-tested, meaning the poor pay little or nothing for the service. "Of course it makes us feel more important that Germany's family minister and the leader of a political party come here and tell us we are right, but they are just jumping on the bandwagon," said Dorothea Schneider, a Frankfurt teacher. "There's a general election coming up and its promises time." Another teacher was even harsher: "The politicians are just here to get airtime. Do they think we're stupid or something?" That explains why there were jeers as Family Affairs Minister Ursula von der Leyen and Social Democratic Party leader Franz M}ntefering adressed the crowd. Working parents who count on daycare are meanwhile at the end of their tether, having used up leave and run out of time with backstops such as grandparents and aunts. Small children are puzzled and sometimes distressed by the stoppages. "Parents feel betrayed," said Eike Ostendorf-Servissoglou who heads the Cologne Association of Working Mothers. Unions call the intermittent stoppages in different regions with almost no warning. For weeks, working parents have had to be geniuses at organizing stopgap daycare of their own when kindergartens close suddenly. They are also furious at having to spend their own money, for example to pay hourly rates to babysitters. Public anger has brought pressure on the unions to halt the strikes and accept what they can get. In one state, Bremen, the union succumbed Tuesday, declaring a moratorium on strikes till August 5.