The Scottish Police Authority (SPA) said it had interviewed frontline staff who believed they were expected to hit targets that officially do not exist.
In its most critical analysis of the new single force yet, the watchdog warned it was "not evident" that those subject to so-called consensual stop-searches were aware of their right to decline.
The number of stop-searches carried out has soared in recent years, sparking concern from a human rights group.
Overall national figures were down in 2013-14, the first year of the single force, but only because of a dramatic 20% drop in Glasgow, which the SPA said had suffered "disproportionate" searches. Figures rose across eastern Scotland.
The SPA report said: "Some officers indicated that they felt pressure to conduct a certain number of searches. This view was confirmed by the same representatives of police staff associations."
Mass stop-searches, it found, were viewed as "business as usual" by officers in the west but new in the east and north.
It added: "The majority of police officers interviewed agreed that many of those who are searched on a non-statutory basis may not be aware that they have a right to decline."
Most stop-searches in Scotland are consensual or non-statutory and may, theoretically, be refused, including most carried out on children and young people. Police have no legislative powers to search someone for alcohol.
The SPA gave the police until September to respond to recommendations designed to beef up protections for those searched - one-third of whom are children or teenagers - and make sure they are aware of their right to refuse.
Brian Barbour, the SPA member who chaired the scrutiny task group, said: "People need to be better informed of their rights, including the right to decline non-statutory search. And we need more research to better understand the longer-term impacts of stop and search on particular groups in our communities, especially younger people.
"Police Scotland's tactical police approach to stop and search is built around searching the right people, in the right place, at the right time. We support that approach. This report is about making improvements to stop and search. It is not about making judgments on stop and search. We hope that through the work we have done, and working together with Police Scotland on the next steps, we can also reduce the polarisation of views that has grown around this issue in the last year."
Police insiders acknowledge this will present real challenges for the force.
Wayne Mawson, the assistant chief constable in charge of such policy, insisted that officers were not under pressure. He said trying to push up the number of searches would make it harder to achieve his actual targets, which are to have a higher level of "positive" searches, where something illegal is found.
The senior officer denied that telling subjects they have a right to refuse a search would present problems. He said: "If you have no other grounds for a search and the guy just says 'No', then that's it, the end of the contact. But if there are other factors the officer may move to a legislative search."
The SPA questioned the quality of information about stop-searches, warning they could not be properly audited because they did not contain names. It is not clear, for example, if individuals are targeted over and over again.
The body questioned what impact the tactic was having on crime. Figures are down in Glasgow and Aberdeen, the highest crime areas. But the former has the highest level of stop and search and the latter among the lowest.
There were 640,000 stop-searches in 2013-14 but only 34 complaints, said Mr Mawson.