The Lib Dems want the Scottish Government to consider bringing in additional leadership and resources, and will call on Justice Secretary Michael Matheson to address concerns about how the force is being led.
However, the general secretary of the Scottish Police Federation (SPF) said the suggestion was “ridiculous”.
Chief Constable Phil Gormley announced on Friday his decision to go on leave, after it emerged he is the subject of a bullying complaint from Assistant Chief Constable Malcolm Graham.
Scotland’s most senior officer was already being investigated by the Police Investigations and Review Commissioner (Pirc) following a complaint by Superintendent Graham McInarlin.
A third complaint, from Inspector Aimee Canavan, is being considered by the Scottish Police Authority (SPA).
Mr Gormley denies the accusations, which could lead to his dismissal if proven.
Mr Matheson will address Holyrood on the single force this week following a request from the Lib Dems for a parliamentary statement.
Party leader Willie Rennie said: “There is no chairman or chief executive of the Scottish Police Authority and now we have no chief constable. “There is a vacuum of leadership in the whole organisation.
“That is why we need the Scottish Government to address the situation and consider whether additional resources and leadership are required.
“It might be necessary to draft in senior officers from other forces in the United Kingdom.”
But Calum Steele, general secretary of the SPF, said Mr Rennie’s comments were “nonsensical”.
He said: “This suggestion ignores two fundamentals – appointments of chief officers are made by the SPA and the chief constable has to be involved in that process by law.”
Deputy Chief Constable Iain Livingstone has taken over leadership of Police Scotland in Mr Gormley’s absence and is believed to have reconsidered his decision to take early retirement.
A Scottish Government spokesman said: “The Cabinet Secretary for Justice will address MSPs in a parliamentary statement later this week.
“Deputy Chief Constable Iain Livingstone will lead Police Scotland through this period of absence, and he is well equipped to deliver the leadership required.”