The company suffered a data breach which it announced in February; at that time, it said it had shut down a security vulnerability on 23 January but was unaware of any data leak at the time.
LMW, one of the bigger property valuers in Australia, counts the big four banks - ANZ, Commonwealth Bank, Westpac and NAB - among its clients.
In the announcement of the second incident, LMW said on Thursday that a total of 76.873 files were present in the data dump, all part of the original 137,500 documents which were stolen initially.
The data in question is "property valuation and some personal contact information of home owners, residents, and property agents, including first and last name, residential address, and contact numbers".
"We recommend all impacted individuals continue to remain vigilant against a potential risk of receiving phishing and other spam communications from organisations purporting to be LandMark White or any one of our lending clients," the company said.
"It is quite possible that over the coming weeks and months further subsets may be reposted.
"In this eventuality, we will continue to take steps to assess and if possible remove the documents as quickly as possible. However, if there is no new data published, LMW does not intend to repeat the advice above."