Foreign aid groups say a $15 million boost to Australia's contribution to the Rohingya crisis in Bangladesh could limit the damage from the impending monsoon season.

The additional funding will be used for food delivery, shelters, medical services and counselling for survivors of sexual violence, and brings Australia's total pledge to $46.5 million since September 2017.

According to United Nations estimates, about 900,000 people are living in packed camps in Bangladesh and a recent downpour has authorities concerned about the upcoming monsoon season.

Oxfam Australia's humanitarian manager Meg Quartermaine said while they hadn't heard details of how quickly the assistance would be available, there was an urgency to provide increased support.

"There is a need for essential services and to help relocate refugees in risk areas," she told AAP in a statement.

"The monsoonal rains could soon cut vulnerable people off from accessing key drinking water sources and aid distributions, which could be devastating for pregnant women, elderly or disabled people and children."

Ms Quartermaine recently visited the camps in the Cox's Bazar area, as did Save The Children's director of policy Mat Tinkler.

"This kind of funding is desperately needed and very much working," he told AAP.

"That is money that is literally saving lives on the ground in Bangladesh right now."

The refugees poured into Bangladesh to escape a military crackdown in myanmar adventure tours, where it's reported the military committed atrocities such as mass rapes, murders and burning villages.