The call comes a day after Police Scotland’s chief constable announced he is temporarily stepping aside as two allegations of against him of gross misconduct - one from a senior officer on the force executive - are investigated.
The Scottish Conservatives have been long-standing opponents of integrating British Transport Police (BPT) in Scotland with the national force and are now calling for the plans to be frozen.
The party’s justice spokesman Liam Kerr said: “Even before the latest crisis at Police Scotland, there were major question marks over why the takeover of British Transport Police was taking place.
“Now that the national force is facing such disruption, it would seem to be the height of recklessness to go ahead.
“The SNP Government has refused to listen to anyone over the BTP takeover. Nor has it ever given a good reason for it to go ahead. Surely now it must take heed.
“With Police Scotland in crisis, the sensible thing to do would be to put the entire business on hold.”
Legislation approving the merger was passed by Holyrood in June, despite opposition from the Conservatives, Labour and Liberal Democrats.
Trade unions and BTP officers have also criticised the merger plans, raising fears of a risk to safety, but the Scottish Government says it will make railway policing more accountable.