UPDATE 1-Angola kicks-off public debate on new constitution

* President to keep grip on power under draft constitution.

* New charter expected to delay elections until 2012.

* Vice president to replace prime minister in new charter.

(Adds proposal to replace prime minister with a vice-president in paragraph 2)

By Henrique Almeida

LUANDA, Nov 4 (Reuters) - Angola kicked off a public debate on Wednesday about a new constitution that is likely to continue President Jose Eduardo dos Santos's grip on power and delay elections until 2012, a senior government official said.

The ruling MPLA party presented a draft charter that keeps the president as the head of government and commander in chief, as is currently the case. Its proposal, one of three, would replace the prime minister with a vice president.

The MPLA, which holds more than a two thirds majority in parliament, also wants to hold both legislative and presidential elections under one single poll, a move likely to delay presidential elections scheduled for this year until 2012.