NAIROBI, Jan 19 (Reuters) - Lecturers at Kenya's public universities started an indefinite strike on Thursday over poor pay, joining doctors who have been striking for more than five weeks and deepening a crisis in public services as the country heads towards elections.

Two unions, the University Academic Staff Union (UASU) and the Kenya University Staff Union (KASU), say their members will refuse to work at Kenya's 33 public universities until their demands are met. UASU mainly represents lecturers and KASU's members are mainly administrative and technical staff.

"Teaching staff are being underpaid and this has gone on for a long time. We want professors to earn what politicians get," Robinson Oduma, the UASU chapter head at Masinde Muliro University of Science and Technology in the western town of Kakamega, told Reuters by phone.

Kenyan lawmakers are among the most highly paid in the world, taking home around 1.2 million Kenyan shillings ($11,500) per month, including allowances, according to Justine Musila who runs the parliamentary watchdog website Mzalendo.

The average annual income for Kenya's 46 million citizens is $1,340, according to World Bank data.

Professors are demanding a 400 percent pay rise to bring them into line with legislators, said Oduma.

The striking doctors want a 300 percent pay rise, which they say was promised to them in 2013. They also accuse the government of failing to stock public hospitals with basic medicines and supplies of items such as gloves.

No government spokesmen were available for comment on Thursday, but officials have previously said the government does not have enough money to pay the salary increases.

The strikes come as President Uhhuru Kenyatta is battling a slew of corruption scandals ahead of his bid to seek a second term in office in an election due in August.

Authorities are investigating tens of millions of dollars alleged to be missing from the Health Ministry, National Youth Service and from ministries issued cash by a Eurobond offering. ($1 = 103.8000 Kenyan shillings) (Editing by Gareth Jones)

Source-Thomson Reuters Foundation