The Tharaka Nithi chapter of the nurses' union has maintained that members will go on strike on November 21.
This is unless the county implements the November 2017 return-to-work formula.
Mr Fabian Marigu, county Secretary-General of the Kenya National Union of Nurses (KNUN), said he has tried in vain to engage officials in Governor Muthomi Njuki's administration.
The official regretted that despite lengthy talks, patience and attempts for the deal to be implemented, nothing had been actualised.
Addressing journalists at Chogoria on Saturday, Mr Marigu said they will have no choice but to join their colleagues in the countrywide strike.
“Unless our county government implements the agreement, nurses will boycott duty from midnight November 21. People should prepare for the worst."
Mr Marigu noted that it is very risky for health services to be paralysed during the rainy season, when outbreaks of diseases such as cholera are witnessed.
The only solution, he said, is for their employer to honour the agreement.
On November 7, KNUN issued a 14-day strike notice in a letter copied to the health minster and the chief executive officers of the Council of Governors and the Salaries and Remuneration Commission.
According to the agreement, nurses were supposed to be paid an annual uniform allowance of Sh15,000 and risk allowances of between Sh20,000 and Sh25,000, depending on their job groups.
The signing of the agreement ended a five-month strike that dealt the country’s health system one of its biggest blows in a long time.