Investors in WA saw their rental income surge after the median house rent climbed by 6% to $370 in the December quarter, according to the latest report from the Real Estate Institute of Western Australia (REIWA).

Rents for units and apartments have also delivered healthy growth of 3%, to a median of $350 per week.

"This means that overall rents in Perth are now at the $360-per-week mark, which represents almost 11% growth in rents over the last year," said REIWA deputy president David Airey.

First homebuyers continued to dominate the Perth market, snapping up properties in the cheaper suburbs which resulted in a dramatic fall in the median house price.

Over the December quarter, the median price of homes in Perth dropped by 4% to $418,000. This represents a decline of 11% since its peak in December 2007, according to Airey.

"The further decline in the median price is largely attributed to the growing share of first homebuyer activity, which pushed cheaper property sales. Homes valued between $250,000 and $450,000 experienced a 5% increase in share of sales in the December quarter," he said.

Conversely, Airey noted that sales of homes in the $600,000 to $1m range have fallen - shedding 5% of market share since September.

Mandurah bucked the overall decline in values with the median price surging by 6% to $393,000. "The sales volume in Mandurah is up around 9%, indicated that the Mandurah market may have bottomed out and is now picking up," said Airey.