The election is on 30 December with Prime Minister Sheikh Hasina, who earned international praise for accepting the refugees who fled a military crackdown in Myanmar, seeking a record fourth term.
The Election Commission ordered authorities in Cox's Bazar to prevent refugees being exploited during election campaigning, Bangladesh refugee commissioner Mohammad Abul Kalam said.
"This is a security measure. The embargo also applies to NGO workers. They cannot go inside the camps unless it is an emergency," he told AFP.
Police said extra roadblocks would be set up around the camps.
Over 720,000 Rohingya Muslims fled what the UN called ethnic cleansing in Myanmar's Rakhine state after August 2017. There were already nearly 300,000 refugees in the overcrowded camps.
More than 450 police will be deployed in the camps alongside border guards and community police, a spokesman said.
Thousands of troops were also put on law and order duties across the country Monday amid escalating poll violence, said a military statement.
Media reports said some 30,000 soldiers were joining more than 20,000 paramilitary forces already deployed.
At least six people have been killed in the election violence while the opposition Bangladesh Nationalist Party (BNP) says at least 152 of its candidates have been attacked.
The BNP meanwhile criticised Bangladesh star cricketer Mashrafe Mortaza for being a candidate for the ruling Awami League.
One-day international captain Mashrafe is now campaigning after leading Bangladesh to a series win over West Indies this month. The BNP said though that Mashrafte could not be a candidate when he earns public money as a cricketer.
"We welcome youngsters like him joining politics. But the law cannot be different for a superstar and a layman," opposition spokesman Rizvi Ahmed told AFP.
"Mashrafe is a paid cricketer of Bangladesh Cricket Board (BCB), a government body. So we protest him taking part in an election when we see our people are getting dropped for lame excuses," he said.
Bangladesh law bars salaried public employees from contesting elections. Several opposition candidates have been disqualified because they have government jobs.
Mashrafe receives taka 420,000 (A$7,106) a month from the board.