After rising above $1.42 in February to its highest level against the dollar since April 2018, sterling lost some ground versus the greenback in March.
The dollar index, a measure of the greenback's value against six other major currencies, hit as high as 92.919, its strongest level since November last year.
"The central bank's recent proactive stance with its interventions ... seems to be here to stay in the near term," they wrote in a note, citing increased nervousness over inflation. "This adds another layer of support for the real."
As part of the guidelines, financial authorities will introduce three indicators to help monitor the dollar funding and operation of non-banking companies, the finance ministry said.