By Jennifer Hill

LONDON (Reuters) - First-time buyers are spending a third of their take-home pay on their mortgage, a survey shows.

Homeowners in their 20s spent 32.4 percent of their income on meeting mortgage costs in June, according to the Woolwich.

Its research reveals a growing home ownership burden, amid rising house prices and interest rates.

The situation is worst for young homeowners in London, where typical mortgage repayments eat up 40.5 percent of income.

The figures compare to an average of 20.1 percent of income for homeowners of all ages.

People who manage to get on the property ladder in their 20s are now paying an average of 586 pounds per month, up 66 percent in the past five years, the data shows.

Andy Gray, head of mortgages at the Woolwich, believes the situation will worsen, pushing the median first-time buyer age beyond the current 29.

"For those in their 20s not already on the property ladder, the outlook for getting on it doesn't look good, especially with interest rates likely to rise further," he said.