The house had a potential health and safety risk for the public so the buyers were not allowed to enter it.
"At the open homes people were just looking at the outside and looking through the windows," she said.
The new owners planned to restore the 1930s bungalow if possible, based on meth contamination results.
They were also planning to develop the back of the 1067sq m section into town houses.
The overseas-based vendors were "super excited" to sell the old family home for above CV, Mayne says.
"It just goes to show how valuable the land is at the moment," she said.
Real estate agents Julie Harris and Kim Vaireka openly marketed the property as a former P lab and it still attracted a lot of interest.
With affordable housing in high demand, the auction was well-attended with competitive bidding, Harris said.
"In the end the auction was fought over by two bidders. Sadly, when the first bid came in at $700,000 a number of people, hoping for a bargain, quickly found themselves out of the game. However, we're delighted with the result as this problematic property now has a bright future."