The course has been altered this year with 18 bends removed. Organisers estimate the changes will make times about 45 seconds faster than in previous years.
The forecast is for a dry day with light winds and a maximum temperature of 13 degrees which would help a record attempt.
One of Tergat's rivals will be Olympic champion Stefano Baldini, who has won celebrity status in his native Italy on a par with Kelly Holmes in Britain since his triumph at last year's Athens Olympics.
Tergat finished 10th in Athens after suffering stomach cramps. But he won the Lisbon half-marathon on 13 March in the secondfastest time ever of 59min 10sec, beating Baldini and world champion Jaouad Gharib.
Last year's champion Evans Rutto of Kenya, who missed selection for Athens, is also back to defend his title.
Rutto, 27, has finished first in each of his three marathons and won by half a minute in London last year despite tripping over a metal security barrier and sustaining cuts to his knees.
