Bahraini authorities have refused to release a baby from prison whose mother has fallen ill, according to a rights group.

Zainab al-Khawaja, 32, is serving a three year and one month prison sentence for multiple convictions that include twice tearing up a photo of Bahrain’s King Hamad bin Isa al-Khalifa.

Khawaja has been in Issa prison since March, where she is held along with her 17-month-old son Abdulhadi.

The Gulf Centre for Human Rights (GCHR) reported on Monday that authorities refused Khawaja’s request to release her son to his father while she is unwell.

Khawaja said she was suffering from flu and is unable to take care of her son. She is also concerned the child may catch her illness.

On Sunday, Khawaja’s husband, who was not identified by the GCHR, went to the prison and was told his son's release "was not allowed”.

Khawaja’s mother, Khadija al-Mousawi, was refused access to the prison to care for her grandson.

Mousawi accused Bahraini authorities of treating her grandson as a prisoner.

“It has become clear to me that my grandson Abdulhadi is no longer only accompanying Zainab in prison, but rather a prisoner himself who cannot leave regardless of the situation,” she said.

Khawaja remains in jail despite Bahrain’s Foreign Minister Khalid bin Ahmad al-Khalifa 7 April pledge she would be released. He was speaking during a news conference with US Secretary of State John Kerry.

More than a month later, on 9 May, the foreign ministry said Khawaja would be released on humanitarian grounds because of her children.

However, at a meeting with prison administration, Khawaja was told that they did not have to act on the statement by the foreign ministry.

At that meeting Khawaja said that she was told the judge who sentenced her had made no decision on whether she would be released.

In a letter written from prison, Khawaja said that her release would only be of consequence if Bahrain changes how it treats its people.

“If nothing changes for the people of Bahrain, then my staying in jail or release is not of great consequence,” she wrote, in a letter published by Buzzfeed.

Her sister, Maryam, told MEE that Khawaja's continued imprisonment was part of a "pattern" in which Bahraini authorities have failed to deliver on their promises.

"The question is not about why they haven't released Zainab, but rather why they (Bahraini authorities) do not generally deliver on their promises," she said.

Khawaja comes from a family of activists, and her father Abdulhadi al-Khawaja is serving a life sentence for his alleged role in the 2011 uprising that initially called for democratic reform, and later demanded the fall of the monarchy.

Bahraini authorities claim to have embarked on a reform process over the past five years – aided by close ally Britain – which has seen an overhaul of the security and justice sectors.

However, activists have argued that the situation has worsened, and increasing numbers of Bahrainis are being imprisoned and allegedly tortured.

Bahraini authorities could not be reached for comment on Khawaja's case on Monday.