Thousands of Kenyan doctors who have been on strike for over a month risk being fired if they do not return to work by Wednesday, government officials said.

The walkout by Kenyan doctors and nurses since December 5 has devastated public health services in the country, where few can afford private care.

The medics on Friday rejected a 40 per cent pay rise offer from the government, demanding the full implementation of a 2013 collective bargaining agreement (CBA), which assured them a 300 per cent raise and other improved conditions.

READ: Kenyan doctors reject government pay offer

"We are calling upon the doctors again, to take the offer by the government and resume work," said Peter Munya, the chairman of the country's Council of Governors.

"We have agreed that those who don't resume work, then the process of taking disciplinary action against them begins on Wednesday."

Mr Munya said the doctors would be issued with dismissal letters, and their vacant positions advertised.

"Striking doctors should consider the plight of Kenyans in public hospitals and resume work. The county and national government has given a very reasonable offer which they need to consider," he added.

The Kenya Medical Practitioners, Pharmacists and Dentists Union (KMPDU) has argued that the offer failed to take into account other agreements mentioned in the CBA, from the need to better equip hospitals to funding research and addressing the security of doctors at work.

However the government has brushed aside the CBA, calling it defective as it did not have "input and blessings" from the Salaries and Remuneration Commission — a constitutional body set up in 2010 to review the salaries of public servants.

The strike has been a major embarrassment for President Uhuru Kenyatta in the run up to August elections in which he hopes to win a second term in office.

Newspaper editorials have urged the government to give the poorly paid doctors a decent wage while Kenyans on Twitter point to endless corruption scandals while healthcare providers struggle to make ends meet.

The latest move to outrage the union was a decision by lawmakers just before Christmas to award themselves Ksh10 million ($95,000) each as an exit package ahead of the elections.

"When the government loots it has no limits but when doctors ask for fair pay the president says he has limits," the union tweeted last week.