The presiding officers said DPS was now working with the relevant security agencies to investigate the incident, but stressed there was "no evidence that any data has been accessed or taken at this time".
In a statement emailed to The Register, the Australian Signals Directorate, an intelligence collection and detection agency similar to the National Security Agency in the U.S., confirmed it is working with the Department of Parliamentary Services to secure the government's network but offered no indication about the suspected source of the attack.
"We have no evidence that this is an attempt to influence the outcome of parliamentary processes or to disrupt or influence electoral or political processes", the Parliament's presiding officers said in a statement.
No exact details were provided as to the nature of the compromise, but the reset of all user passwords is said to have occurred to secure "the network and protecting data and users".
The top MPs who oversee Parliament confirmed that security agencies were now investigating the incident and urgent action has been taken to protect the network, including the changing of all passwords.
"The necessary steps are being taken to mitigate the compromise and minimise any harm", ASD said in a statement.
Local cyber-security experts have suggested the hack likely came from a foreign state.
"There would be lots of juicy correspondence between staffers about who is doing what and dirt files on different politicians", Hanson said.
"If I was a nation state, or dare I say any hacker looking for state secrets, this is the crown jewels".
There has been a breach of security on Parliament House's IT network.
"Accurate attribution of a cyber incident takes time and investigations are being undertaken in conjunction with the relevant security agencies".
Opposition Leader Bill Shorten said he was satisfied with the response so far.
Parliament's presiding officers said DPS had made "substantial strides" in strengthening cyber defence of IT network at the house in since 2012.
In 2016, Australian Prime Minister Malcolm Turnbull committed AUD$400m over ten years to improving cyber security.