Prime Minister Tony Abbott has rejected the suggestion Sydney and Melbourne are in the midst of a housing bubble, saying most Australians wanted house prices to rise so they could secure their future.

Opposition Leader Bill Shorten yesterday accused Abbott of behaving dangerously by ignoring the bubble warning issued on Monday by Treasury Secretary John Fraser, and asked if the government had a plan to improve housing affordability to help young people enter the market. In response, the PM accused Shorten of wanting to lower house prices.

"This Leader of the Opposition is a menace to the economic welfare of the people of Australia. Australians have mortgages and the last thing they want to see is the decline in their most important asset," Abbott said, reports The Australian Financial Review.

"That's what the Leader of the Opposition is saying, he is saying that people's houses are worth too much. Do not trust this man with your house price. Do not trust this man with your superannuation. Do not trust this man with your future and do not trust this man with the Government of Australia because what he wants is your house to be worth less."

The PM's modest Sydney home, which he bought for $351,000 in 1994, would today sell for $1.5 million, according to a real estate agent asked to comment on the property by The Daily Telegraph.  The newspaper also asked for an opinion on Shorten's Melbourne home in Moonee Ponds, which was purchased for $842,000 in 2009 and would today be worth $1 million.