A university professor in Guangzhou, Guangdong province, has lodged an appeal with local authorities and is considering legal action after he was fired on the grounds that he had violated the national family planning policy.

Cai Zhiqi and his lawyer went to the Guangdong provincial human resources authority on Tuesday to submit an appeal, asking the South China University of Technology to reinstate him.

He had worked as a chemistry professor at the university since 2009, but was fired in November after the university's family planning office discovered he had two children.

In December, he lodged an appeal directly to the university, but his request to be reinstated was rejected, causing him to appeal to a higher authority on Tuesday.

"If the appeal is rejected by the human resources authority, we will seek labor arbitration or file a lawsuit against the university," Cai said.

In response to Cai's appeal in December, the university wrote a letter confirming that he had been fired and explaining the reasons.

The letter, dated Jan 16, said Cai had violated the nation's family planning policy and had been sacked in accordance with Guangdong's family planning regulations.

Cai claims the university's position conflicts with existing regulations that give those who study abroad the right to a second child.

Cai's first child was born in the United States in 2007 when he was working overseas, and the other was born in Tianjin in 2010. The first child is a citizen of the US, and the second is registered to live on the mainland under the household registration system.

He cites a regulation from the National Population and Family Planning Commission in 2002 that allows people from the Chinese mainland who are studying overseas to have a second child if they lived abroad for more than a year.

"Before we returned to China, my wife and I had been living in the US for more than two years," he said.

The university refused to comment on Cai's appeal on Tuesday. However, in earlier media reports, it was quoted as saying that the 2002 regulation applies only when both partners live and study abroad for more than a year. In Cai's case, they said, his wife was not studying in the US, but simply accompanying her husband.

Since being sacked by the university, Cai has been working part-time for a friend's chemical company.

"My family life was greatly affected after I was sacked by the university. Most of the time, I worked with my lawyer to prepare the lawsuit. I hope that I can return to the university one day," he said.

Cai's wife, who began studying for a doctoral degree at the university in September 2012, was also asked by the university's family planning office to give up her studies. The office said a family with two children would affect the university's annual performance in family planning assessment by the local government authority.

But she claims the university gave her a verbal promise that she would be allowed to continue her studies, as the decision to fire Cai had already brought significant losses to the family.

"It was only a verbal promise. I am not sure that my wife can still study in the university in the future," Cai said.

Cai and his wife are not alone in their predicament. China's decades-old family planning policy had resulted in a number of university professors and celebrities being punished in recent years.

In a recent case, film director Zhang Yimou was fined 7.48 million yuan ($1.24 million) for violating the policy. Authorities in Jiangsu province said Zhang and his wife had three children before marriage without obtaining permission from officials.

The family planning policy, which was introduced in the late 1970s to rein in population expansion, limited most urban couples to one child and most rural couples to two children if the first child was a girl.

But the policy had been adjusted several times in recent years. According to a recent decision at the Third Plenary Session of the 18th Central Committee of the Communist Party of China, Chinese couples will be allowed to have two children if one of them is an only child.