The shooting follows a deadly ambush that left five more policemen dead on Monday.
The latest attack occurred in the northern coastal town of Zemmouri on Tuesday afternoon, L'Expression reported on Thursday.
The paper said two Islamists "wearing shorts so as not to arouse suspicion", blended in with the crowd of beach-goers and opened fire on the two policemen at point-blank range.
One of the policemen died on the spot while the second was wounded to the neck and chest. A woman who was nearby was also injured.
The assailants took advantage of the panic the attack had sown, stole the policemen's weapons and fled, L'Expression said.
Security sources have blamed the Salafist Group for Preaching and Combat (GSPC), the largest active Islamist hardline group in Algeria, for the attack.
The night before, the GSPC ambushed a convoy of soldiers and policemen not far from Zemmouri.
Five soldiers and two policemen were killed in the ambush, which occurred on Monday night near Boumerdes, 50 kilometers east of the Mediterranean coastal capital Algiers.
The ambush was the deadliest to target the security forces since June, when 14 soldiers were killed in an ambush in the Bejaia region, 260 kilometers east of Algiers.
Nearly 40 people have been killed in July and August and 340 since the start of the year in incidents involving armed fighters, according to officials and the Algerian media.
The war broke out in 1992, after the military seized power to prevent an election victory by an Islamist party. The conflict has already claimed some 150,000 lives, mostly civilians.