Senior Labor and Coalition parliamentarians say the Greens have “questions” to answer as Senator Jordon Steele-John faces an internal probe into claims of inappropriate behaviour toward women.

Senator Steele-John this week took leave from the Greens party room after current and former members wrote to leader David Shoebridge asking him to investigation allegations spanning “almost a decade”.

Reporting has since revealed that the party’s Western Australia branch kept a 47-page crisis management plan detailing how to manage media coverage of any allegations against Senator Steele-John.

It also instructed staff to monitor any related chatter on social media from party members.

Senator Shoebridge – who clinched the Greens leadership late last month with Senator Steele-John’s backing – has denied any knowledge of the document or the allegations.

Cabinet minister Tim Ayres told News24 on Sunday there were “questions” for the new leader to answer.

Asked if he thought Senator Shoebridge knew of the allegations before they became public, he directed the queries to minor party’s leader.

Senator Ayres also denied ever hearing any rumours about Senator Steele-John.

“No, I had not heard rumours of these allegation,” he said.

Opposition frontbencher Sarah Henderson also said “the Greens have a lot of explaining to do”.

“It is appropriate that there should be a proper, I hope, independent inquiry into these allegations,” she said, speaking to the same broadcaster.

Senator Steele-John has rejected the claims against him, saying they try “to assert I am someone I am not”.

“I have referred this matter to the WA Greens, so that a fair, independent process can be commissioned that upholds the principles of natural justice and ensures procedural fairness for everyone involved,” he said.

“These claims are made without specifics, any allegation of this nature is extremely serious and must be treated accordingly.

“If someone has made an allegation, I am prepared to address it.”