Warsaw stocks rose 0.3 percent by 1355 GMT.
Budapest's main index gained 1 percent, after OTP CEO Sandor Csanyi said the region's biggest independent lender planned to buy at least five banks in the next two years. .
Strong Czech, Hungarian and Polish manufacturing indices (PMI) may have also provided some help to assets in the region.
But demand for the region's currencies was reduced by a strengthening of the dollar, with Catalonia's independence vote weighing on the euro.
The leu still firmed 0.3 percent against the euro to 4.586, setting a four week high.
"It is getting an expected boost from higher interbank rates," a Bucharest-based trader said.
Romanian Prime Minister Mihai Tudose criticised the central bank late on Friday for failing to curb a rise in interbank interest rates, driven by inflation expectations. Electricity and gas tariffs for households rose from Oct. 1.
The bank set the three-month ROBOR interbank rate even higher on Monday. The ask level, set at 1.71 percent, was the highest since late 2014.
The zloty traded weaker by 0.1 percent, at 4.313, down 0.1 percent, near 6-1/2-month lows touched last week.
Poland reported a higher than expected PMI manufacturing index of 53.7 for September, underpinning that economic growth remains strong. But the zloty was unable to benefit from the good figures.
Hungary, which calculates its own index with different methodology, reported an even higher figure, at 59.3.
The forint also eased, staying near its weakest levels against the euro since May. A new round of monetary easing measures launched last month has been keeping it under pressure.
The measures pushed down Hungarian government debt yields to record lows, but a rise in US and euro zone debt yields triggered profit-taking since last week.
Hungary's yields rose further on Monday, with the 10-year bond at 2.63 percent, up 5 basis points from Friday.
Elsewhere, the Czech Republic also reported a strong PMI index at a higher-than-expected 56.6.
The crown danced around the 26 psychological line against the euro, near its strongest levels since the central bank (CNB) removed a cap which had kept it weaker than 27.
Expectations that the CNB will continue to lift its interest rates in November buoy the currency, but a huge amount of long crown positions held by foreigners keeps a lid on the unit.