More than half of parents with young children are spending at least a fifth of their monthly salary on childcare, researchers have warned.

The survey of 1,620 respondents found that nearly a third of parents in the UK with children under five are spending 30% on a nanny, nursery or childminder.

Yet while almost half of parents say the biggest problem with childcare is cost, 25% say they very rarely or never ask their family for help with it, the study for GoodCareGuide.co.uk found.

While 55% of parents say the care their child receives is always of the highest standard, 31% say they are happy with the standard of care most of the time but there are occasions when they worry.

Common complaints included children being able to leave unnoticed, being bullied by others at the nursery or suffering food poisoning as a result of being fed while in childcare.

The survey also asked parents how stressful taking their child to nursery for the first time was. It revealed that 12% of parents said it was one of the most stressful things they have undertaken, more so than starting a new job or planning their wedding.

It found that parents choosing a nursery are most concerned about quality care (67%). Fourteen percent said cost was the priority, followed by location and the staff's qualifications and experience.

Andy Major, the director of GoodCareGuide.co.uk – an independent TripAdvisor-style website for the care industry – said: "These statistics show what a large percentage of the parents' paycheques in the UK are spent on childcare.

"While the government is proposing to bring in 20% tax relief on childcare, they need to ensure that all parents are benefiting from the changes and it's not just another change that won't impact those who really need it.

"The results also demonstrate what an independent nation we are, with one in four parents choosing not to rely on their extended families for their childcare needs, despite the financial repercussions."